refactored fxa.js to shared folder.  moved email authentication to an fxaUser object.  adding restmail validation.
Splintering off fxa user handling to FxAUser object (WIP).
added testcases for ftu and settings.  some tweakage to fxa.js and fxa_user.js
updates to stabilize testcases and cleanup for push.  add 'make fxa' to Makefile for easy testcase execution