Update pool copy cleanup

This small addition just makes sure that the .opensesame.pool temporary pool folder is cleaned up upon exit.
Bump to 2.9.0~pre30
Update android setup script
Bump to 2.9.0~pre31
Add PyGaze to modules() function
Change default sound_buf_size to 1024
- Avoids stuttering on Windows systems
Update debian/changelog
Bump to 2.9.0
Bump to 2.9.0~pre1
Use round() rather than float-to-int conversion in canvas._gabor() and canvas._noise_patch()
- Closes #283
Improve detection of Exception message in osexception
- Closes #285
Add debug._msg() for debugging even outside of debug mode
- For use in development *only*
Fix font widget in sketchpad
- Initialize only once
- Don't apply when controls are programatically changed
- Closes #284
Update debian/changelog
Print initial debug message only in debug mode
Update mouse back-end documentation
Application-wide keyboard shortcuts for tab switching
Add close-current-tab action
- Improve keyboard shortcuts for tab management
Work around a race condition when dropping items on sequences and loops
Better focus behavior when opening new tabs.