This also makes two changes to forms: first, forms can
be set to rename the entity, just like views can. This is
enabled for anything using makeModel. Secondly, when switching,
if the new form has a view whose names matches the old form's active
view, it will switch to that same-named view, instead of using
the default view for the form.

So, for example, you'll stay on the "side" view for coins, even when
switching between forms.

Also updates the Blender script.

It can now generate views on a per-object basis, and uses
whole collections so that many objects can be grouped together.

Also add some tweaks to the process-model script that I managed to lose.

Entities derived from models can now have volumes

This also updates the model-processing script to automatically
insert the model data into the appropriate source file.

I also significantly rewrote the process-potrace-model-forms.py
script, as well as the blender-model.py script. Most of the other
scripts are old; I removed some personal info from them, so they
don't work properly now.