Add onready handler (bug 1014783)

Tried to add onmatch in place of onready as per https://github.com/mozilla/browserid/issues/2648 but found onmatch was never called.

In the end this implements the same solution we have in the current webpay implementation.

I've started to clean up anon function names as the recent webdev discussion came to the conclusion modern browsers can provide enough info to pinpoint where they are at.