Review

New version of sketch widget. Sketches have a move method, and drawing works differently internally.
Updated sketchTests to work with new sketch widget.
Button widget has new setText method (not really new, just changed back).
New button test on buttonTests page.
Fixed formatting problem with slider readout.
Added new slider test to sliderTests page.
An animationTests page now exists, but is effectively empty right now.
id problem in toc-structure fixed.