Android (Fragment): Added Immersive Mode support

While looking into the Android tests, I noticed fragments where using Immersive Mode in some tests. I decided to port the immersive mode function to fragments. 
- Formatting
- Minor changes to AndroidApplicationBase
- Worked in my tests. Probably best if someone else confirmed as well.
- Better logging for AndroidVisibilityHandler exceptions
- (Off topic: issue 1337!)