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.
Parent and Anchor are sometimes different RigidFrames.  A fixed frame's
parent is the thing it directly connects to and defines itself in.  The
anchor is the deepest body/mobilized body on which it's transform is fixed.

Point taken on base and anchor being used sloppily though.  I need a way to
conceptually communicate that the Body or MobilizedBody is a
root/base/anchor articulating segment on which RigidFrames can be stacked.
On Oct 8, 2014 12:08 PM, "Ajay Seth" <notifications@github.com> wrote:

> In OpenSim/Simulation/Model/FixedFrame.h:
>
> > +	
> > +protected:
> > +
> > +	/** Model Component Interface */
> > +	
> > +	void addToSystem(SimTK::MultibodySystem& system) const override;
> > +	void constructConnectors() override;
> > +	// Frame interface
> > +    SimTK::Transform calcGroundTransform(const SimTK::State& state) const
> > +        override;
> > +	// Helpers for initializing fixed frames
> > +    //--------------------------------------
> > +
> > +    /**
> > +    * Get the fixed transform between my anchor segment and myself
> > +    *
>
> What is an anchor segment? The description for the return is more
> accurate. Is it "between" or the transform that describes this frame in the
> parent frame. I would remove use of anchor if you are using parent. You
> also use "base".
>
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