mozilla: use 'MozillaPlugins' registry entry to register VLC plugin dll, which means plugin no longer needs be copied to FireFox/Mozilla plugins folder

Much too late to do that sort of thing. Closes #871.

- direct3d: enable user control of hardware YUV pixel format (basically a RGB pixel format can be forced)

Closes #792

activex: UrlCombine() API is actually buggy, use replacement API already present on mozilla (needs loads of testing)

memcpy approach with proper check to avoid buffer overflow.
Afterall, I think we should discard *huge* SAPs anyway.

current locale and variables in UTF8