Migrate to Android Studio/Gradle project structure

Android Studio import of ADT structured project; Delete old directory
structure
Fix .gitignore

Add .gitignore, .idea, app specific gradle files
Remove accidentally added gradle cache files
Update Idea files after VCS integration
Tidy up resources
remove app/build from repo
Remove huge default project inspection
Fix xml Lint errors
Move class members to local variables where appropriate
remove local.properties from repo
Remove unneeded returns in void method
Remove redundant local variables

CursorLoader variable doesn't need to be declared, can just return the
new.
Lint edits to avoid NPEs

relocating calls to avoid accidental NPEs in Edit Activities
More Lint fixes: this time, related to contracts