refactor: completely redesigned rendering, now done in elisp side

Most of the inspector machinery I was basing the contrib upon made it
difficult to implement features such as collapse/expand and separate
inspectors. I was also cramming the code full of (let ((*istate* ))
hacks and such).

It's true a lot of ideas and concepts are effectively being
reimplemented. But the new code is much cleaner and more succint.

It should also be much faster, as it places a lower load on the
network.