Orientation2

This one tidies up the new orientation features based on feedback.  It includes the following changes:

* convenience method for ostream << operator for converting InterfaceOrientation to a string
* convenience method for getting orientation degrees
* renamed getInterfaceOrientation -> getOrientation (returns device orient.)
* added getWindowOrientation (active win orient.)
* added docs, clarified the rational behind `EventSignalSupportedOrientations`'s usage of `BitwiseAndEventCombiner`.