Make first startup more user friendly

[larsen0815]

1. "C:\Program Files\PuTTY\putty.exe" wasn't recognized automatically on the very first startup. I guess it should be no problem to check for the existence either with a hardcoded path or by checking the registry (if such a key is created by PuTTY).

2. Would be nice to automatically import the previous SuperPuTTY configuration (ask user), so no configuration dialog would be shown on the first start.