Added URL parameter autosave

If autosave=0 then nothing is stored in local storage.
Minor code cleanup
Fixed tool selection bug

Selection was incorrect when scrolling.
Combined box hole CSS classes

toontalk-box-hole and toontalk-empty-hole are now combined and code
renamed to use hole instead of empty_hole. Fixes #140.
debug_string for holes is updated
Box holes have drop feedback

Hole is highlighted not the whole box as previously. Also improved
highlighting feedback.
Fixed a bug removing widgets

If the widget's backside didn't implement removed_from_container
Switched to addEventListener from on

JQuery's on interferes with adding multiple listeners and also adds code
complexity with event.originalEvent.
Next robot starts training on drop

When a fresh robot is dropped on a robot's next robot drop area it
starts training.
Box holes in resources no longer highlight
Renamed get_toontalk_widget_from_jquery

For better code readability
Element widgets resize on nests

To fit on the nest. And size is restored when removed.
Element widgets resize in holes
Run button titles fixed

Freshly enabled run buttons had the wrong title. Also disabled run
button given better title.
Re-implemented widget sides

Simpler more robust code now for parent links, nests, and sensor. Still
need to update backside widgets list.
Fixed styling of sensor values

So that they look the same when reconstructed.
Improved the styling of fractions
Update index files

Better sizes for numbers and boxes.
Completed widget side re-implementation

Backside widgets are now also using widgets and backsides.
Updated some test files