Fixed onLeaveContainer bug in keyboard-a11y plugin

[Colin Clark]

Hi everyone,

Jacob stumbled across a bug in our keyboard accessibility code while  
working on the new tutorial a couple of weeks ago. I verified the  
issue for him and filed a bug for Infusion 1.1:

http://issues.fluidproject.org/browse/FLUID-2662

I just committed a fix to the issue along with a couple more tests  
verifying that these events are indeed being invoked at the correct  
time.
Jacob and I also did a bit of pair programming to improve the  
tutorial, which can now take advantage of this fix. Keep an eye out  
for a new and improved keyboard accessibility tutorial coming soon.

Colin

---
Colin Clark
Technical Lead, Fluid Project
Adaptive Technology Resource Centre, University of Toronto
http://fluidproject.org