increased width of scene widget, to address problem that dancer disappeared out of scope. however, also reverted previous support for resizing.

Revert "support for resizing experiment window"

This reverts commit 644b7add952172b292fc43c8139be080cc10d4a7.

Conflicts:

	dance-cognition/experiments/experiment.py
refactoring
min relative velocity editable in GUI
less "dramatical" improvisation by increased min relative velocity
updated TODO