Return registration id and identity key when decrypt PreKeyWhisperMes…

…sage

This information is part of the PreKeyWhisperMessage but is required by a
TextSecure implementation.

Check preKeyId isn't null in createSessionFromPreKeyWhisperMessage

Checking for falsey wouldn't catch the case where preKeyId is 0.

Don't modify passed in session in createSessionFromPreKeyWhisperMessage

Release 1.2.0

Fix incorrect method name on Axolotl interface

Update to traceur 0.0.84 and remove outdated traceur-runtime dependency

Refactor the interface to side-effect free

After attempting to use the interface for the first time, I found that it
was not very suitable. Implementing the large Store interface was also
painful.

The new interface is much more functional. All methods are side-effect free,
with the exception of calling the remaining store methods.

I've moved the trust check out of Axolotl as this should be done at a
higher level, in my opinion.

I've also removed the JSON serialisation of the session, as some clients may
want to serialise the session in other ways.

Update compiled library to 0.9.0

Include dist folder in repostiry for bower

Fixed bower ignore file list and create 0.5.2