Code cleanup in various places

Removes old code that isn't used anymore, useless methods, comments, etc.
Fix #150 Gallery closing on orientation changes

The base class's onLogin method was never called in GalleryActivity
because GalleryActivity defined a method of the same signature that
overrides the base class's. That method was being called twice -- once
for the @Subscribe and once for the @Subscribe in the object listener in
BaseActivity.

Overriding BaseActivity's onLogin method and calling super fixes it.