BLK-206 Caching for YouTubeUser username/id pairs

Signed-off-by: Oren Leiman <oleiman@neutral.io>
BLK-226 fix patching
Merge pull request #15 from nio-blocks/patch

BLK-226 fix patching
Merge pull request #14 from nio-blocks/feature/caching

BLK-206 Caching for YouTubeUser username/id pairs
BLK-209 Update youtube block to most recent RestPolling and send management signal on Invalid Creds

Signed-off-by: Oren Leiman <oleiman@neutral.io>