[#36] Add logout method to MeteorClient

- Update ListViewController in Example app to use logout with new button.
- Fix typo in MeteorClient spec
[#35] Greatly simplify BSONIdGenerator.

- Meteor itself uses a simple incrementing integer for message ids, using this simple scheme instead
which has the (now confirmed) benefit of avoiding a memory allocation error that caused a crash in
some cases
- Adding connectWebSocket back in Example appDelegate appDidBecomeActive implementation - this
allows the app to open a new websocket resume the last session if it is backgrounded (but not killed)
- Using simplified id generator correctly now in example app