Adds thread model/collection for managing conversation-level state, such
as unreadCounts, group membership, thread order, etc... plus various UI
improvements enabled by thread model, including an improved compose
flow, and thread-destroy button.
Adds Whisper.notify for presenting messages to the user in an orderly
fashion. Currently using a growl-style fade in/out effect.
Also some housekeeping:
Cut up views into separate files.
Partial fix for formatTimestamp.
Tweaked buttons and other styles.
Adds Backbone-based Whisper.Messages model/collection with local storage
extension. Saves sent and received messages in Whisper.Messages instead
of message map. This will assign a unique id to the message and save it
to localStorage.
Adds Backbone-based view to popup.html
Automatically updates itself when new messages are saved to
Whisper.Messages db from the background page.
Added some shiny new styles, and started splitting up css into multiple
files for sanity's sake.
