Fix for #266

-Extra: Added the appropriate images to drawable folder from Android SDK
source, can be used as alternative if required.
Removed Thumbs.db,added to gitignore
Final fix for #266

-Fix implemented using setIcon() as setIconAttribute() is not valid for
API less than 11
Partial fix for #304
Complete fix for #304
Show link to Market if no openpgp provider installed installed
Issue #295
Change resource name and remove unneeded if from 44232af
Added GPL headers