MainFrame: make bExtOnTop visible to class
Don't drop out of fullscreen when loosing focus

Instead, unset the "on top" flag.
ISR: Render text subtitles relative to the video frame when in doubt.
Text subtitles: Set the default clipping rect based on the rendering target.
About dialog: Make the clipboard output nicer.

Most systems only have one video device so improve the output for that case. Also trim white spaces in the device name.
Testing: Don't force any background color for the Shockwave graph.
Why "C:\tmp.srt"?
Fix some CPPCheck warnings or mark them as intentional.
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...
Fix: x86 and x64 versions conflicted over file associations.

4f465cf8b81f1da800b1bfc57cc48e317d24fbb5 was incomplete for Vista+.

This commit fixes #4064.