Merge pull request #5 from dschreij/master

Improved backdrop functionality and event listening
Remove conflict trace
Merge branch 'master' of https://github.com/dschreij/opensesame_eyelink_plugins.git into tmp
Bump to v0.21
Minor cleanup
Add pupil_size() function and minor cleanup
Respect line wrapping and disable saccade event bug-fix (for now)
Rename exp_eyelink_delay to eyelink_clock_async
Add auto-log option to eyelink_log plug-in
Bump to 0.22
Merge remote-tracking branch 'upstream/master'

Conflicts:
	eyelink_calibrate/libeyelink.py
Conflict resolution of upstream changes

Merged conflicts occurring with 0.22