Also, modify the Blender add-on so that mass can be
computed via density even if a volume is not being included

This adds a CR1632 button cell

(just a credit card for now, though). This also introduces some fixes
to the process-model script, allowing for it to compensate for the
extra height introduced by the line art. blender-model.py is adjusted
to allow for this, and makeModel() now checks for the bottom/extra
values produced by the process.

Auto prey capacity was getting set to false, rather than 'off'.
It was also showing up when it shouldn't have. The blender script
ignores spaces in the view list now. makeModel wasn't including
mass correcetly.

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.

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.

These use a new entity-maker.