Further fixes to EyeTribe functionality and OpenSesame plug-ins

[smathot]

(Ref #19)

A few small but crucial improvements

• Fix a bug in the oskeyboard class with None timeouts
• Randomize the order of the calibration dots in eyetribe calibration, to avoid anticipation

And a larger one (#4aa3f3c), which is a hack that you may or may not want to merge. If not, an alternative will have to be implemented. Basically, it seemed that the locking was not fullproof, so that a heartbeat request could be sent while another request was ongoing. This happened all the time on my system, maybe because I have a slow laptop. At any rate, the way I worked around is by adding a dedicated lock in request().

Other than that, it works pretty sweet now! Great job, Edwin. Just out of curiosity: Is this all your own work, or did you build on another module?

[esdalmaijer]

Just got back from vacation, will merge shortly.

Curious that you experienced multiple requests being sent at the same time. Might indeed be PC slowness (my testing PC for this is a beast), but we should nevertheless acount for it. I like your solution, which is actually more elegant than the separate locks in the EyeTribe class.

Thanks for the compliment! It is indeed my own work. It wasn't very hard, though, as the EyeTribe is a treat to work with. Although the API reference is rather short, it's very complete and you need little more than what they provide. Also, the Python section of the forum is a nice place to share ideas.