Fix: DVD playback issues on some systems.

On some systems, DVD playback could stutter (fixes #5131) or fail completely due to an error related to copy protection (fixes #4969).

This was caused by the way we tried to fetch the DVD chapter information.
(WIP/Broken) Disable the time tooltip shadow for incompatible video renderers.

Some video renderers cause the tooltip shadow to be replaced by an opaque black box.

Fixes #1415.
(WIP/Broken) Try to find out if VMR-7 uses overlays, without luck so far...
Don't force any background color for the Shockwave graph.

This commit fixes #1747.
WebUI: Inform the web interface that no audio stream is available.
WebUI: Make use of new [hasaudio] info.
Capture bar: Try to guess what was intended here.

So far getting the sign of the original biHeight seems to be what makes more sense. Some formats do use negative biHeight so it seems sensible to keep the original sign.