Bug: scope.$.eventHandler passed the wrong boolean to get for includeParents.

I knew this would happen. I first had the boolean around the other way.
Check that if includeParents is included as an argument that it must be a boolean

As I'm checking strictly for false, I don't want developers expecting truthyness.

It could allow truthyness, but I figure I'll be strict on the types as the API may using types to decide which of a set of optional arguments has been given.
v0.6.2