pubsub: Adding topic listing.
Merge pull request #34 from rakyll/missing-listings

pubsub: Adding topic listing
Merge pull request #33 from silvolu/master

Adding regression tests.
pubsub: Poll message and emit events.
Add TODO.
Adding TODO about the immutability of the subscriptions.
Convert message data to base64 and decode on pull.
Merge pull request #36 from silvolu/master

Return Error object for failed Api requests and fixed flaky test.
pubsub: Subscriptions are designed to be persistent. Allow to close without deletion.
pubsub: Subscribe should not involved in persistent subscription creation.
Allow options to be optional.
pubsub: Allow to get a subscription without listening.
Merge branch 'master' of github.com:GoogleCloudPlatform/gcloud-nodejs into eventemitter-subs
Include regression tests to coverage.
pubsub: Adding subscription creation.
pubsub: Fixing undefined callback.
pubsub: Add regression tests.
pubsub: Adding regression tests for subscriptions
pubsub: Improving test coverage.
Merge pull request #35 from rakyll/eventemitter-subs

WIP: EventEmitter Subscription