Implement microphone pass-through in audio engine.

* No way to disable it, it even invades menus.
* Requires very low suggestedLatency (so some platforms are probably b0rked).
Merge branch 'master' into pass-through
Merge branch 'master' into pass-through

Conflicts:
	game/pitch.hh
Merge branch 'master' into pass-through
Reworked Song selector navigation.
- Hiscore always on, no separate mode for that
- Up/down traverse menu where left/right may browse songs, sort modes, type filters or info screens (also jukebox mode)
- New graphical layout is not done yet so the menu is invisible and hiscore display is somewhat b0rked
- Type filter only toggles vocals filter for now
Fix song type filtering (new style).
Minimal UI for the menu.
Merge branch 'master' into pass-through
Some pass-through refactoring and reduce volume ratio.
Option to toggle microphone pass-through.
Configurable pass-through volume ratio.
Fix variable naming.
Optimize pass-through buffer recording.

Don't create new temp vector each Analyzer::input(), but reuse one.
Merge branch 'master' into songmenu
Don't repeat the song title in hiscore and make it less broken.
Merge branch 'master' into songmenu
C++11 support for older gcc with -std=c++0x flag.
Do not do vocals init if there are no vocals. This fixes the crash I introduced a while back. Dummy vocals track is no longer used.
Remove some semicolons.
Don't crash on vocals if no mics are setup.