This mostly helps with mobile Safari

Drawing an SVGImageElement to a canvas goes haywire. This checks for
that behavior and warns about it, and turns off the fine-grained
selection logic.

This fixes the ultra-fast scrolling that was happening in Safari.
It also makes scrolling more consistent in general.

I forgot to undo some changes to the drawImage logic oops

The click-test code skips the pixel test in Safari, since
drawing SVGs to a canvas is, apparently, a buggy mess.
This also adds a bunch of -webkit-user-select properties
to make things unselectable in Safari.

This adds a CR1632 button cell

Some event listeners were being set up instantly, rather than
after the document was fully loaded. This caused them to try
to access a canvas before it was ready, spitting out an error.
The relevant code is now in the DOMContentLoaded block.

Also fix broken attribution for utility poles

That was a Blender thing. Also updates the process-model
script so that it runs some stuff in parallel, which might
make it slightly less agonizingly slow.

(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.

This would cause problems in Firefox