Bump version to 2.0.6

This version brings a bunch of fixes:

• Autoscan should now seek also for DVB-T2 channels, on devices that support it;
• Implement systray show/hide
• EPG algorithm improved to reduce CPU usage
• Unmute audio when the player instance is created (e. g. Kaffeine is loaded)
• Some visual improvements to show <Close> instead of <Ok>/<Cancel> on some windows
• Some changes to allow improvements at translations
• A new record is now enabled when created
• Add support for multipoint LNBf, where DiSEqC is not used
• Fix DiSEqC LNBf satellite select
• Don't ignore weak signals on DVB-T
• Handle special case on devices with a single demux, but multiple frontends
• Add support for DVB-T2 multistream
• better report errors when VLC is not found
• synchronize DVB scan file with latest upstream version

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>