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.
@aymanhab It isn't consistent with Joint usage of parent_body. In Joint's  case we have two components of type Body that we want to differentiate. I called one a parent and the other child to identify which Body is being specified. In this case, we have the class Frame which we already defined to be be a reference frame, so that would be analogous to Joint having connectors for rigid_body_1 and rigid_body_2, since by Body is a rigid body.