Web interface: Be more careful when url encoding things.

Some characters weren't url encoded.
WebUI: Inform the web interface that no audio stream is available.
WebUI: Make use of new [hasaudio] info.
Fix some CPPCheck warnings or mark them as intentional.
What the hell was intended here?!

Trying to make some sense of that code. Without much luck so far...
Lite builds: Fix a minor inconsistency regarding the output directory.

Lite debug builds use "mpc-hc_x??_Debug Lite" while release builds always used "mpc-hc_x??" for both normal and lite builds.
Fix: x86 and x64 versions conflicted over file associations.

4f465cf8b81f1da800b1bfc57cc48e317d24fbb5 was incomplete for Vista+.

This commit fixes #4064.
Language menu: Ensure "Language" always appears in English in menu entry.

If "Language" doesn't appear in the translated string, "(Language)" will be appended automatically.