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