Added BrowserID and some login modifications

There are more changes to be done.
I have talked to the devs and I was informed that they are still working on the new modifications, so I think that it is too early to do some major modifications on out test suite.

I added https://bugzilla.mozilla.org/show_bug.cgi?id=905118, because there are a lot to modify in the tests for now, and I don't want to change all the methods/tests without knowing the result.
Regarding the outcome of the bug, I will start adding the changes.

I am still seeing the old login sometimes with the new one (http://screencast.com/t/XioviT3xvfC), so I think we should wait a little bit more until they finish the work