Running widgets can be dragged and saved

And continue to run when recreated.

Widgets can be made 'runnable'
Fixed a robot create bug

Was causing some unwanted sharing
Widget displays updated less frequently

Every 20ms is better than after every queue run.
Top-level widget toggles running

Clicking on the top-level backside toggles all child widgets. Fixes
Issue #14. (At least as well as can be for now.)
Can toggle all widgets by clicking on document

Since can include running widgets on pages need a way to turn them on or
off. Not a great solution.