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.
> I know that can be made to work in code consistently for all symbols, but I'm not as sure about the "centered" notation here

@sherm1 I'm not sure what you mean about it not working consistently for all symbols.  Still, I can change it for consistency with Simbody.  I just find that the centered notation is exactly what we mean, while the monogram notation was ambiguous to me when I first saw it used.  I had to look it up multiple times to make sure I was using these transforms correctly.