changelog update
ENH: Current state of psychopy.iohub docs
BF: Copied autogenerated x11 ctypes wrapper from pyglet 1.2 (lib/x11/xlib) to psychopy.iohub.devices so that ctypes wrapper can be used independantly of pyglet version installed
Merge remote-tracking branch 'origin/master'
BF: iohub Computer process priority changing methods now catch AccessDenied errors and return True if priority change was successful, False otherwise.

 BF: Removed test from iohub Keyboard device for non existant modifiers property.

 ENH: ioHub process related priority changing methods now also return success status as bool.
ENH: Updated iohub kb device docstr
ENH: Updated GP3 iohub interface

eye tracker interface class cleanup.
Merge branch 'master' of https://github.com/isolver/psychopy
DEL: iohub demo
Merge branch 'master' of git://github.com/psychopy/psychopy
Merge pull request #697 from isolver/master

Misc iohub BF and ENH