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.

Also make 'earth' a valid unit

This usually happens when the window gets unfocused before
the screenshot is done. The promise is now handled properly.
Unhandled promise errors will now cause a popup. The popup
can only appear once now.

You don't have to hld alt to move things past the edge of the
screen now. There was no real reason to include that.