Start to hook up each of the screen modules.

@borjasalguero, @sergi, @OlavHN - I have taken the code that I wrote during the Madrid work week and ported it here, attempting to follow naming conventions as much as possible. There is a lot of duplication in the modules - for instance set-password and enter-password are very similar. I did this intentionally to come up with approaches tailored to the screen and then create a generalization out of those approaches. I am not doing any lazy loading of the modules yet, but this should be possible.

I was able to simplify fxam_navigation.js a bit, and the ability to go forward and back through the states works well.

Items that still need completed:

* [ ] - Hook up calls for check email, create account, authenticate account, reset password.
* [ ] - Error screens for "password too short", "cannot sign in", "cannot create account".
* [ ] - Ensure swiping works (hook up to onhashchange). - is this a requirement?
* [x] - Correct text needs filled in for completion screens.
* [ ] - Reset password link needs to be hooked up.
* [ ] - Center the input elements on focus.
* [ ] - TOS/PP agreements need to be hooked up.
* [x] - l10n of embedded strings for the error screens.
* [ ] - ensure template text matches https://bug905637.bugzilla.mozilla.org/attachment.cgi?id=825368
* [ ] - l10n of strings embedded in the templates.
* [x] - Cleanup - is onBack needed inside of each module?
* [x] - Cleanup - get rid of all console messages.
* [x] - possible lazy loading of module JS.
* [ ] - lazy load the error element and JS

To test, some values are hard coded:

* To follow new user flow - enter `newuser@newuser.com`.
* To follow existing user flow - enter an other email address.
* The only acceptable password is `password`