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 like this find = "calc cheaply". Doesn't that apply to getBodyTransform(state) as well, or is the distinction that the state is already realized to position so it's X_GB is already cached?

Right, exactly. In Simbody's API "get" means "completely free, zero flops". Basically it says you don't have to hang on to the answer to avoid recomputation, you can just call the accessor again.