Remove signin/signup and forgot password from the main site.

Use the dialog instead

issue #900
Updated the tests to do all signing in through the dialog.
Hide the "persona intro" whenenver signing into the Persona main site.
Remove the "Sign in" button from the front page "tour"

issue #3189
include internal api in communication_iframe scripts
Expose internal watch implementation
Prepare internalWatch to receive the proper options
We need to set the origin here
Do a strict check on null-ness of loggedInUser
network.init() needed for auth check
failure callback is triggered unless network.clearContext is called after init
Send internal parameter {silent:true} for silent assertions
Bug 823736 - objects must be stringified between gecko and user js
(Cherry-picked a5eade72a6451e4861cf7f6270085fe2f141effc)
Bug 827558 - rename native navigator.id to .mozId

(Cherry-picked commit 5b7004cdc830d28fc78e28ee29517c83216ec408)
Conflicts:
	resources/static/include_js/_jschannel.js

Original changes from include.js applied to _include.js
Log a message if invalid JSON is passed in to .watch or .get, do not continue processing.
Cleanup of the internal_api

* Remove logging messages
* Declarations all external dependencies at the top of the file.
* Spacing
* Set loggedInUser to null in onLogout
internal.watch calls back with error on bogus json
Use String(e) instead of e.toString(), make the watch error test asynchronous.
Manually merging setOrigin and .watch tests

from SHAs:
* f971f4a5944cb1647b9b93a7fc5d1493153e8d99
* ed0cb7a23986e25be43ee71f9f907779fb07ca8d

forceIssuer portions will have to be manually merged later.
Merge pull request #3238 from mozilla/b2g_dev_prepare_internal_api

B2g dev prepare internal api

@jedp gave this an r+. I added some more tests. I give this an r+ too.