autosaved URL parameter bug fixed

Sign was interpreted incorrectly
Fixed bird animation bugs

That led to nest widgets not knowing their parent nest.
Bird animation no longer assumes bird parent
Improved error message.
Robot stopped in mid-cycle still animating

So setting animating flag to false was wrong.
Fixed a bug watching robots remove widgets

The next step was being run from two places.
Added error checking and reporting.
Improved robot widget removal

Simplified the code and fixed a problem removing a backside of a widget.
Fixed typo
Added warning for double removal

Of the front side of a widget.
Updated test programs