Completion of non-listed commands, and little typo check.

I’ve added most not ¨documented¨ (On the README.md atleast) launch commands, that i feel, is useful for users who want to customize even more steamgrid usage. That’s why I haven’t the `-steamdir` one, which is more of a troubleshooting one, in case it doesn’t find it. I could add it as an alternative method to the troubleshooting `Fails to find steam location` entry to complete it even further.
Also took the time to check for typos and little corrections to do. Some are extremely pointless and futile, as correctly writing the macOS according to their stylized name, adding a couple of commas, correcting apostrophes and correctly writing size units per regulation.

Author: PoorPocketsMcNewHold

README.md

@@ -2,21 +2,21 @@
 
 **SteamGrid** is a standalone, fire-and-forget program to enhance Steam's grid view and Big Picture. It preloads the banner images for all your games (even non-Steam ones) and applies overlays depending on your categories.
 
-You run it once and it'll set up everything above, automatically, keeping your existing custom images. You can run
+You run it once, and it'll set up everything above, automatically, keeping your existing custom images. You can run
 again when you get more games or want to update the category overlays.
 
 # Download #
 
-[**steamgrid-windows.zip (4.4MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_windows.zip)
+[**steamgrid-windows.zip (4.4 MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_windows.zip)
 
-[**steamgrid-linux.zip (4.5MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_linux.zip)
+[**steamgrid-linux.zip (4.5 MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_linux.zip)
 
-[**steamgrid-mac.zip (4.6MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_mac.zip)
+[**steamgrid-mac.zip (4.6 MB)**](https://github.com/boppreh/steamgrid/releases/latest/download/steamgrid_mac.zip)
 
 # How to use #
 
 1. Download the [latest version](https://github.com/boppreh/steamgrid/releases/latest) and extract the zip wherever.
-2. *(optional)* Name the overlays after your categories. So if you have a category "Games I Love", put a nice little heart overlay there named `games i love.banner.png`. You can rename the defaults that came with the zip or get new ones at [/r/steamgrid](http://www.reddit.com/r/steamgrid/wiki/overlays).
+2. *(optional)* Name the overlays after your categories. So if you have a category “Games I Love”, put a nice little heart overlay there named `games i love.banner.png`. You can rename the defaults that came with the zip or get new ones at [/r/steamgrid](http://www.reddit.com/r/steamgrid/wiki/overlays).
     * Add the extension `.banner` before the image extension for banner art: `games i love.banner.png`
     * Add the extension `.cover` before the image extension for cover art: `games i love.cover.png`
     * Add the extension `.hero` before the image extension for hero art `games i love.hero.png`
@@ -29,14 +29,18 @@ again when you get more games or want to update the category overlays.
 4. *(optional)* Generate a some API Keys to enhance the automatic search:
     * [SteamGridDB API Key](https://www.steamgriddb.com/profile/preferences)
     * [IGDB API Key](https://api.igdb.com/signup)
-5. Run `steamgrid` and wait. No, really, it's all automatic. Not a single keypress required.
+5. Run `steamgrid` and wait. No, really, it's all automatic. Not a single key press required.
     * *(optional)* Append `--steamgriddb <api key>` if you've generated one before.
-    * *(optional)* Append `--igdb <api key>` if you've genereated one before.
+    * *(optional)* Append `--igdb <api key>` if you've generated one before.
     * *(optional)* Append `--types <preference>` to choose your preferences between animated steam covers or static ones Available choices : `animated`,`static`. Default : `static`. You can use `animated,static` to download both while preferring animated covers, and `static,animated` for preferring static covers.
     * *(optional)* Append `--styles <preference>` to choose your preferences between the different covers styles from steamgriddb. Available choices : `material`,`white_logo`,`alternate`,`blurred`,`no_logo`. Default: `alternate`. You can also input multiple comma-separated choices in the same manners of the `--types` argument.
     * *(optional)* Append `--appids <appid1,appid2>` to only process the specified appID(s)
     * *(optional)* Append `--onlymissingartwork` to only download artworks missing on the official servers.
-    * *(tip)* Run with `--help` to see all available options.
+    * *(optional)* Append `-nonsteamonly` to only search artworks for non-steam games added onto the Steam client.
+    * *(optional)* Append `-skip<preference>` to skip searching and downloading parts from certain artwork elements. Available choices : `-skipbanner`,`-skipcover`,`-skiphero`,`-skiplogo`. For example: Appending `-skiplogo -skipbanner` will prevent steamgrid to search and download logo and banners for any games.
+    * *(optional)* Append `-skipsteam` to not download the default artworks from Steam.
+    * *(optional)* Append `-skipgoogle` to skip search and downloads from Google.
+    * *(tip)* Run with `--help` to see all available options again.
 6. Read the report and open Steam in grid view to check the results.
 
 ---
@@ -59,14 +63,14 @@ again when you get more games or want to update the category overlays.
 - Loads your categories from the local Steam installation.
 - Applies transparent overlays based on each game categories (make sure the name
   of the overlay file is the name of the category).
-- If you already have any customized images it'll use them and apply the
+- If you already have any customized images, it'll use them and apply the
   overlay, but keeping a backup.
 - If you have images in the directory `games/`, it'll search by game name or by id and use them.
 - Works just as well with non-Steam games.
 - Supports PNG and JPG images.
 - Supports games with multiple categories.
 - No installation required, just extract the zip and double click.
-- Works with Windows, Linux, and MacOS, 32 or 64 bit.
+- Works with Windows, Linux, and macOS, 32 or 64 bit.
 - 100% fire and forget, no interaction required, and can cancel and retry at any moment.
 
 # Something wrong? #
@@ -75,7 +79,7 @@ again when you get more games or want to update the category overlays.
 - **Fails to find steam location**: You can drag and drop the Steam installation folder (not the library!) into `steamgrid.exe` for a manual override.
 - **A few images were not found**: Some images are hard to find. The program may miss a game, especially betas, prototypes and tests, but you can set an image manually through the Steam client (right click > `Set Custom Image`). Run `steamgrid` again to apply the overlays. If you know a good source of images, drop me a message.
 - **No overlays found**: make sure you put your overlays inside the `overlays by category` folder, and it's near the program itself. This error means absolutely no overlays were found, without even taking your categories names into consideration.
-- **It didn't apply any overlays**: ensure the overlay file name matches your category name, including possible punctuation (differences in caps are ignored). For example `favorites.png` is used for the `Favorites` category.
-- **I'm worried this is a virus**: I work with security, so no offense taken from a little paranoia. The complete source code is provided at this [Github repo](https://github.com/boppreh/steamgrid). If you are worried the binaries don't match the source, you can install Go on your machine and run the sources directly. All it does is save images inside `Steam/userdata/ID/config/grid`. It does connect to the internet, but only to fetch game names from you Steam profile and download images into the Steam's grid image folder. Nothing is installed or saved in the Windows registry, and aside from images downloaded it should leave the computer exactly as it found.
+- **It didn't apply any overlays**: ensure the overlay file name matches your category name, including possible punctuation (differences in caps are ignored). For example, `favorites.png` is used for the `Favorites` category.
+- **I'm worried this is a virus**: I work with security, so no offense taken from a little paranoia. The complete source code is provided at this [Github repo](https://github.com/boppreh/steamgrid). If you are worried the binaries don't match the source, you can install Go on your machine and run the sources directly. All it does is save images inside `Steam/userdata/ID/config/grid`. It does connect to the internet, but only to fetch game names from you Steam profile and download images into the Steam's grid image folder. Nothing is installed or saved in the Windows registry, and aside from images downloaded, it should leave the computer exactly as it found.
 
-If you encounter any problems please [open an issue](https://github.com/boppreh/steamgrid/issues/new). All critics and suggestions are welcome.
+If you encounter any problems, please [open an issue](https://github.com/boppreh/steamgrid/issues/new). All critics and suggestions are welcome.