Remote key mapping fixes & Screen saver refactor

3 screensavers - backdrop, logo and none
UI on appearance setting page to select
new photo screen saver on the way
use Ctrl-Shift-E to bring up the current selected screen saver

Experimental Fast Forward & Rewind mapped to Ctrl-F & Ctrl-B - No OSD display

Remote key fixes as in http://mediabrowser3.com/community/index.php?/topic/5978-bug-remote-control-issues-with-newest-build-30520116543/