Added Base Adapter snippet to the README.md

Author: Matt Oakes

README.md

@@ -6,6 +6,7 @@ These snippets are designed to make it quicker and easier to create Android apps
 Avaliable Snippets
 ------------------
 
+ - `ad-baseadapter` A stub BaseAdapter implementation which uses the [view holder pettern](http://developer.android.com/training/improving-layouts/smooth-scrolling.html#ViewHolder)
  - `ad-logdebug` Debug log with a message
  - `ad-widget` The basics needed to get started with creating a custom widget