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.
>  Point then would be analogous to Frame.

Yes, that's a great way to think about it! A general Point is just a Frame without the axes. A Station is an "anchored" point. The class hierarchy could be 
```
Point
    AnchoredPoint
    MesurementPoint
```
The `AnchoredPoint` ("Station") constructor would take an `AnchoredFrame` and a `Vec3` offset. A `MeasurementPoint` ("point of interest"?) would take any `Frame` and some method for calculating the offset from that frame as a function of state.

While there might be better names available for types of points, I like the idea of making the Point hiearchy and Frame hierarchy as identical as possible to make the concepts easy to convey. For example, you could attach a spring to any Anchored{Frame,Point} but not to a Measurement{Frame,Point}. And an AnchoredFrame's origin could be an AnchoredPoint.