lots of updates - thumbs and fanart working

pruned a lot of plex stuff out
thumbs working
fanart working
images are being copied locally right now, take a long time on first
browse.

still tons to do!
We have playback!

Removed a bunch of Plex specific code, changes image cache location -
got playback working!
Merge branch 'master' of https://github.com/xnappo/plugin.video.plexbmc