Use popup_menu class for sketchpad context menu
- Fixes translation issue (closes #287)
Parse variables in video_player plug-in (closes #288)
Bump to 2.9.1~pre2
de_DE small revision

I found some improper translations and also unitized the use of "Du"
instead of "Sie", which was inconsistent before.
Update translation files
Heisenberg Update & Revision

Translated the new strings, corrected some errors, and unitized the use
of "Du" instead of "Sie", which was inconsistent.
Merge German-translation update and recompile translations
Bump to 2.9.0~pre3
Update 32x32 sketchpad-element icons
Improve detection of translatable strings
- Now also parse extensions and plug-ins
Fixed a bug when reducing and then canceling the number of cycles in a loop
Fix a mistake in the synth docstring example
Register custom fonts on OpenSesame start
- Fixes font-style issue in sketchpad canvas
Bump to 2.9.1
Include PyQt4 plug-ins in Windows build
- Fixed missing image codecs
Merge remote-tracking branch 'upstream/heisenberg' into heisenberg

Conflicts:
	debian/changelog
	libopensesame/misc.py
	opensesame.nsi
Merge branch 'heisenberg' of https://github.com/dschreij/OpenSesame into heisenberg

Conflicts:
	debian/changelog
	libopensesame/misc.py