Refactor libphonenumber.validateNumber into libphonenumber.parseNumber,
which encapsulates the try-catch pattern used in number parsing and
returns an object of info about the input number rather tha throwing
since we expect to get some invalid number inputs the user is typing.
In the conversation model,
* Separate phone number validation from search token updating.
* Perform token update before save if the number was valid.
* Stop storing unneeded number variants as conversation properties.
// FREEBIE
After a message is saved asynchronsly, fire an event and pass the
message attributes to frontend listeners via the chrome-runtime API.
This behavior is similar to the 'storage' event fired by localStorage.
Getting up and running with IndexedDB was pretty easy, thanks to
backbone. The tricky part was making reads and writes asynchronous.
In that process I did some refactoring on Whisper.Threads, which
has been renamed Conversations for consistency with the view names.
This change also adds the unlimitedStorage permission.
