with previous versions of Android Studio working properly with Release Candidate 4 (December 4th) or newer:
FATAL EXCEPTION: main java.lang.NoClassDefFoun
This has nothing to do with gradle. It's an update for Google Play Services. The LocationClient class has been replaced with the new FusedLocationProviderApi.
LocationClient
FusedLocationProviderApi
Check this answer: Android play services 6.5: LocationClient is missing