Merge branch 'master' into songmenu

Conflicts:
	game/screen_songs.cc
Merge branch 'songmenu' of github.com:performous/performous into songmenu
Sync flashing cover to song BPM. Note loading hack needed for BPM info, needs to be fixed before release.
Merge branch 'songmenu' (local unpushed work from my desktop box)

Conflicts:
	game/screen_sing.cc
New style for note lines, using harp string colors for C and F and dotted line style for sharp notes.
Text rendering bugfixes and improvements. Disable Cairo AA in favor of high res textures. Do not let Pango render text in black before rendering on top of that with Cairo.
Clean up GL attribute setting.

- Do not attempt to set accumbuffer size (avoids warnings about not being able to)
- Set stencil size to zero (we don't actually need one and zero works for me)
Reduce songparser warnings about too short tracks when the track isn't supposed to exist.
Prevent spurious keyboard controller events on LCTRL or ALT combinations.
Fix pause and volume control broken by previous commit.
Better fix for the too few notes issue.
usability fix in menu handling in screen_playlist

esc now closes the menu instead of changing the currently opened one.
Merge remote-tracking branch 'origin/master' into webserver