frontend: Add SNR approximation in dB for VU+ Solo2 NIMs.

Thanks to jacques1971 for the percentage data. The approximation
might improve with more data, currently it's a very loose
approximation.
Fix intermittent missing first character in plugindescription
MediaPlayer: Do not show inforbar when going to menu
Display remaining time since an event was aired as negative.

Signed-off-by: Littlesat <littlesat99@yahoo.com>
On all screens: Move from green to key_green etc.

Signed-off-by: Littlesat <littlesat99@yahoo.com>
Give the About screen a label on the green button.

Signed-off-by: Littlesat <littlesat99@yahoo.com>
[SSatFinder] fix BSOD.
[VideoMode] cleanup and add '3DSoundMode' and 'bypass_edid_checking'.
[About] add CPU model and CPU cores to information.
Tweak feed detection code.
openvix: build 618
MessageBox: Add possibility to get more choices than only yes/no

In addition remove a whitespace. Now you can give a list with options.
Could e.g. later be used to add save timeshift as recording at the
Timeshift protection.
Adjustments for more choices of Messagebox at skin_default.xml
[PTSTimeshiftState] requires skins tweaks, please see skin_default for what.
[EventView] slight tweak.
openvix: build 619
Limit choices visiable at once to 5 for MessageBox

As there is limited space on a screen...
And also center it in hight.
[MovieSelection[ fix BSOD.
[AudioSelection] add some new options.
Simplify the Sleeptimer.