Disable animations between chooser and gameplay screens

Ditch them because:
1. They were in the wrong direction when we consider the chooser to be the
topmost screen of the app.
2. It is unusual for full window transitions to be used within modern apps
except for navigation to and from the Settings screen.
Add SVG source for action bar shadow
Fix error in ab_shadow.svg
Merge pull request #128 from doopl/master

Disable animations between chooser and gameplay screens