Add basic test coverage of toArrayBuffer function
Move message and conversation storage to IndexedDB

Pretty easy, thanks to backbone.

Also adds the unlimitedStorage permission.
Asynchronize first convo render
Conversation cleanup/minor refactor
Unkink rendering event chain
Consolidate message callbacks

Register the runtime callback at the top level view rather than having
each conversation view register independently.
Also refactors Layout into InboxView.
Destroy all globals

Well, not *all* globals..
Fix scroll when re-opening a conversation
Get rid of Layout global

Instead, trigger and listen for events on the conversation collection
object.