Implement crop functionality

- Added crop button (but not to widget) and crop functionality
- Aspect ratio left at 1:1 for now

Fixed crop quality and aspect ratio

- Quality isn't shot on cropping anymore
- Changed aspect ratio to 960:800 which seems about right (for LG Lucid
at least)

Crop bugfix and code cleaning

- Code more intuitive now
- Fixed bug where app would crash upon leaving mid-crop
Target the Google+ Photos crop activity

Also unhardcode crop ratio. We're only hacking it a little bit now...
Minor formatting/cleanup