End to end primary flow on the signup page.

* Adding unit tests for network.addressInfo
* to the XHR mock, adding info needed to test primary/secondary flow.
* Adding a BrowserID.Mock.Provisioning to handle mocking out provisioning capabilities.
* Creating a new User.createUser that handles creating users on either primaryies or secondaries.
* Adding unit tests for the signup page for primary, updating old tests for secondary.
* Starting a shell of error messages and success markup on signup page.
* Starting to hook up the dialog, adding loads of tests.  Secondary based user creation good again.