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 misinterpreted your earlier comment:
>The point of making the RigidFrame subfamily was so modeling connections could be of defined type, connector<RigidFrame>, and guarantee that model component connected to is was actually connected a Body.

I totally agree that RigidFrame should NOT have the specification that it connects to a Body and should not provide a getBody() (or getAnchorBody(), whatever). Furthermore, RigidFrame should not depend on or require the existence of Body. For the purposes of computation ONLY it should provide access to the underlying MobilizedBodyIndex and that should be in an "advanced" section of the API. Body already provides this access and I am simply saying this access should move into the base RigidFrame class.