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.
We can be a bit more definitive. Perhaps:

A RigidFrame is a reference frame (or simply a Frame) that represents the most fundamental rigid element in a multibody system. It is inherently massless and has no inertial or material properties associated with it. However, it is a Frame upon which Forces can be applied and used to connect to other RigidFrames via Joints and Constraints. In Simbody this concept is personified by the SimTK::MobilizedBody. Therefore, the only requirement of RigidFrame in OpenSim, is that it directly corresponds to a SimTK:: MobilizedBody. When the SimTK::System is created, a RigidFrame can always provide its underlying MobilizedBody (e.g. `getMobilizedBodyIndex()`).