#645 modify/optimize source code to support unit test
#646,#645 initial checkin of unit test code
#645 make sure conversations are saved
#647 add gradle project configurations for sdk and sample
#647 update README with android studio instructions
Merge branch 'release-20141117-0.5.12' into feature-20141117-unit-test
#646 fix unit test configuration for gradle
#645 fix gradle file so autocomplete can work
#645 disable additional database test case due to problem with robolectric
#645 add mock core data factory
#638 refactor OPUser
#663 Add Android Annotations in gradle file
#639 refactor OPConversation
#639 Use user id for call lookup
#639 enable contacts deletion in Profile picker
#639 a few fixes and simplifying call lookup and creation
#664 handle incoming call in Application
#639 ChatFragment refactoring
#667 update sdk target
#667 update target sdk to 21