Content Provider conversion

DatabaseFactory is now a content provider
Fixes issue where GerritService would load project list data
 in the background and the ProjectList would never be notified
 about it.
Fixes issue where the database would not change on changing gerrit instance
There should be no user interface/feature changes here, just A LOT of back-end
 improvements.
Removed CWAC-LoaderEx library as we are now using a content provider instead
AndroidManifest: Registered Content Provider, don't export data
Removed ProjectsListLoader, CursorLoaders provide all the functionality required

Change-Id: I627eb59a1a99a96eb84eede7199f4cbcfe6d49a7