Merge pull request #27 from silvolu/master

Fixes for runInTransaction
Merge pull request #30 from silvolu/master

Pass to request an empty object instead of true
Adding AUTHORS and CONTRIBUTORS.
Adding missing jsdocs.
Automatically acknowledging messages if autoAck is set.
Merge pull request #31 from rakyll/master

pubsub: Auto-ack messages optionally
pubsub: Implementing subscription listing.
Fixing wrong parameter name on jsdoc.
Merge pull request #32 from rakyll/missing-listings

pubsub: Implementing subscription listing.
Adding regression tests.

* Coverage for datastore.