Begin unsucking kodi admin panel

Begin unsucking kodi admin panel

After hitting 300 lines of drunken extensions to make up for defects
discovered during parties, I decided to start cleaning up this code.

This is the beginning -- enough changes to need to save my place before
doing anything more radical. Goals (partially achieved, for some
definition of achieve):

 - Use yattag for html formatting instead of gross blocks of `print'
   that don't correctly escape anything
 - Centralize hacks to work around Kodi JSON RPC deficiencies
 - Code split up so that it can be reused in normal party goer interface