* Add autofocus to the appropriate button or input fields.
* Enable the form to be submitted using the keyboard in "sign_in.html"

includes updates to the example primary and tests.

Change browserid.org urls to persona.org, introduce static.login.persona.org for all static resources.

Fixing up a bunch of cancel primary verification flows. This is when a user is verifying with a primary and they hit ccancel and are redirected back to BrowserID.

Flows:

* Required email cancel.
* Cancel add user to current account.
* Cancel create new user.

Others Items added.

* Add a "cancel" button to the sample RP.
* Defer how state should be handled for primary user verification from dialog to state.

issue #983
issue #1036

implement a more generic mechanism to enable local testing and development of primary support - allow SHIMMED_PRIMARIES to be provided which stuffs a auth url, provisioning url, and public key in our cache

implement a more generic mechanism to enable local testing and development of primary support - allow SHIMMED_PRIMARIES to be provided which stuffs a auth url, provisioning url, and public key in our cache