Completely overhaul test RP. One page, all APIs.

Still needs CSS and returnTo love, but should be much more functional than
the existing test RP.

Basically, I wanted a single page where I could test all of the APIs, unexpected interactions, etc.

This does that.
No quotes but self-closing tags what year is it

(In sane-er words, no need to self-close these, it's HTML5!)