MPV VDR-Streamdev-Client

Changes:
+ fix bug in creation of timer with channel groups
+ make script-message names more consistent
+ minor bugfixes

+ now with channel groups support a la vdr
+ bugfixes

Fixes the channel switch action (blue key)

Contains various fixes:
- fix path to bash in windows (Many thanks to jirie@vdr-portal.de!)
- fix minor OSD issues
- confirm deletion of timers
- more config options for osd