Advanced option page: Update value while typing in editbox.

Fixes #4625
Advanced option page: Be consistent about the names.
CMyFont: Check that the fallback CreateFontIndirect doesn't fail in debug mode.

It should never happen in theory.
VobSubFile: Ensure m_langs is properly initialized and avoid magic numbers.
SyncRenderer::CGenlock: Make sure all member variables are initialized.
SyncRenderer::CGenlock::MovingAverage: Don't over-allocate memory.
Don't force any background color for the Shockwave graph.

This commit fixes #1747.
Why "C:\tmp.srt"?
WebUI: Inform the web interface that no audio stream is available.
WebUI: Make use of new [hasaudio] info.
What the hell was intended here?!

Trying to make some sense of that code. Without much luck so far...