DeprecationWarning when running a yield statement

[Jeff]

The viztask.waitMouseDown command has been updated and no longer expects the viz.Data object to be passed as an argument. Use the following instead:

def example_trial():
	startTime = viz.tick()
	response = yield viztask.waitMouseDown( None )
	print 'response at: ', viz.tick() 
	reactionTime = response.time - startTime
	print reactionTime