Refactorying Storage layer

Android ads SQLite features and this provides a way for Client implementations to inject their own storage providers.
Adding TestActivity to support build

Using TestActivity instead of LoginActivity to base generic tests off of.
Renaming from AndroidClient back to Simperium
Moving MemoryStore to support package
Implementing MockClient
MockBucketStore now implements Android package storage
Fixing package for test
Removing out of date comment
Standardizing logging tag
Fixing javadoc warning
Configuring gradle builds for publishing to sonatype