Merge pull request #194 from bhariharan/unstable20

Merge unstable to unstable20
Add the option for the app to handle cleanup upon revocation of access token
Default to true.
Renamed method
Merge pull request #195 from bhariharan/revoke_refresh_token

Add the option for the app to handle cleanup upon revocation of access token
Update Sample Apps with BroadcastReceiver to handle access token revocation
Move receiver to the SDK and update sample apps
Merge pull request #196 from bhariharan/revoke_refresh_token

Update Sample Apps with BroadcastReceiver to handle access token revocation
Merge branch 'unstable' into unstable20