It is crucial that the Xtext Builder comes after the Android builders, because the Android builders are destructive, i.e. they wipeout the whole gen-folder.
clean ups: organize imports, removal of unused variable, avoidance of raw types, explicit return types
Deprectated SynchronizedUtil as it is no longer needed.
Enhanced AndroidPreferences
 - mark fields as read (no warnings anymore)
 - check for explicit type 
 - code cleanups
Improved BundleProperty

 - removed duplicate set entries
 - mark fields as read (no warnings)
 - some code clean ups