Add animation on buttons  of the main menu
Add animation on paypal button of the donation screen
Show ChangeLog on app upgrade (display changelog from previous version)
Add ChangeLog in the navigation drawer (display full changelog)
Eula: use DialogFragment + fix rotation
Fix: Some menu items of navdrawer must not be marked as checked
Add "exit application" dialog on back pressed of the main screen
Replace volley source code with the volley jar.