BF: fixes to quick fix issues found on Linux/OS X

- All examples (not including eye tracker examples folder, not yet
tested) run on all 3 platforms.
- Mouse button bug on Linux found and reported to issue tracker, making
the ioMouse example run, but not due what it should.
- OSX OK, other than the ioHubServer having to be killed every time the
program ends; must be somemthing related to an OSX specific API being
used, as this does not happen on other OS's. So pyobjc related APIs
being used will be a good place to start looking.
RF - coder demo-menu discovers iohub subdirectories

also:
- ioMouse.py - converted \t to 4 spaces
Merge pull request #299 from isolver/master

BF: fixes a few issues that were quick to do but were causing some examples not to run, or none to run at all when tested off my dev box.
Merge pull request #300 from jeremygray/master

iohub demos get added to coder demo menu
Merge branch 'master' of github.com:psychopy/psychopy
BF: PIL can't always be imported as it should (from its documentation) Thanks Wouter Kruijne.