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.

Also styles selects differently if they have their 'disabled' value

They were getting drawn once for every entity, and were also getting
moved around weirdly.

These use a new entity-maker.

The entity resizes itself to the default size for its form

Also fix a bug with wrong sizing for multiple forms.
The last default size encountered was being used, rather than
using the one that matched the default form.

Also make some performance improvements: naturals
are sorted by name, instead of being constructed
to be sorted by size. This significantly speeds up
loading, because those objects were expensive to make.

Forms allow for one entity to have multiple distinct sets of
views and sizes.

Also switches to using localeCompare

The device pixel ratio wasn't being respected

Some lines were being drawn at non-integral positions.
The x and y coordinates are now floored before use.

Entities can now be rotated. This does not affect
their height. For now, they can only be rotated by
45 degrees at a time. I will work out something nicer
later on.

Permalinks now just stick the base64 string into the
fragment portion of the URL, rather than using a
query parameter. This should reduce spam in the server
logs, and also keep scenes more private.

The definition needed a number.

This only applies for the grow/shrink buttons on the sides

Buttons/inputs/selects use the Coda font, and inputs
are more evenly sized

This affects the world height, the entity scale, and all view numeric inputs.
The fields are no longer of type 'number' so that text can be entered.