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 songmenu
Don't repeat the song title in hiscore and make it less broken.
Merge branch 'master' into songmenu
Merge branch 'master' into songmenu
Merge branch 'master' into songmenu
Merge branch 'master' into songmenu

Conflicts:
	game/screen_songs.cc
	game/song.hh
Merge remote-tracking branch 'origin/songmenu' into songmenu
Merge branch 'master' into songmenu
Text rendering/layout cleanup. Needs more work but I'll commit a WIP version before going on holiday. Feel free to revert if it breaks something (passed my quick testing with no apparent functional changes).
Untested specular and emission mapping in core shader.
Try something for issue #21.
Revert "Try something for issue #21."

This reverts commit 37cd07e018970345faf1638e29b6d89417f0efca.
Fixed drumkit parsing from controllers.
Fixed midi drumset type in controllers.
Merge branch 'master' into songmenu

Conflicts:
	game/screen_songs.cc
	game/screen_songs.hh
Implement keyboard shortcuts for sort change (TAB) and filters (F5-F8).
Song browser UI concept test. drawInstruments function rewritten.