User request: draggable clamp, stand, window

[oliver-phet]

May I suggest making the C clamp, test stand and window draggable end objects, so that students can investigate how the length of the medium plays a role?

[arouinfar]

I can't imagine that the model would support a variable string length. However, I'll follow up with JO and KP about this the next time this sim is revisited. Unassigning myself until work resumes on this sim.