Implement Statistics

- The database will now be moved to the application Documents folder on
the first launch. We need to do this to be able to write to the
database.
- Add Statistic table to the database
- New statistic will be created if the user doesn't have a statistic
for a specific level at the end of the level or updated if the user
already has a statistic for this specific level.
- Add score display to the game layer
- Minor cleanups and more comments
Merge branch 'master' of https://github.com/TeamRedundantTeam/SoundOutPhonics

Conflicts:
Sound Out Phonics.xcodeproj/project.pbxproj
Sound Out Phonics/Menu/LoginLayer.m
Merge branch 'master' of https://github.com/TeamRedundantTeam/SoundOutPhonics

Conflicts:
	Sound Out Phonics.xcodeproj/project.pbxproj
	Sound Out Phonics/KBPlanetEarth.ttf
	Sound Out Phonics/Menu/LoginLayer.m