Fix: Big Picture support

Updated Big Picture support due to changes in the addon
Update: Cosmetic changes for the music visualiser

Added zoom / pan effect to artist fanart. Also changed the timings on
the text scroll basing it on system time instead of the player time.
Hopefully reduces some of the overhead causing lag on some low power
devices.

I'll add an option to disable it entirely soon.
Added: Skinned the TextViewer window

ie: Changelog window for addons, etc.
Cleaned: Unnecessary code breaks / text