Matt ayman frames

Redo of the merge of Frame, RigidFrame, FixedFrame, Station and Marker ModelComponents along with code to convert Marker to new format for serialization/deserialization and inclusion of FrameSet in model.
@sherm1 @msdemers @aseth1 or @chrisdembia Please review and let us know your feedback.
hmmm. I think I like findTransformBetween() the best.  As Ajay mentioned, it's cleaner to read, and using "find" matches the Simbody convention.  I'm favoring changing all "calcs" to "finds".