chunk: Convert types from numpy.ndarray to array.array.

Just seeing if this is worthwhile.
Add requirements.
tests/plugins/seasons: Fix a single test.

-1 error, +1 success.
utilities: Fix a docstring and a couple tests.
Remove tests.helpers.

Only one function which is easily elidable.
tests/utilities: Split up a couple tests.

Producing tests out of thin air!
tests/plugins/physics: Make erroring test into failing test.

Better than before.
chunk: Fix composite_glow().

Ugh. Such gnarly code. :c But tests work!
chunk: Fix last remaining errors.

Only a couple of failing tests remain.
chunk: Fix OOB test in check_bounds().

Actually catches stuff now. Well, more stuff, at any rate.
chunk: Introduce ci() macro for doing chunk indices.

Stands, obviously, for "Chunk Index."
chunk: Move glow tables out of globals and into a function.

Leaking names isn't cool. Leaking names like "x" and "i" is doubly uncool.
chunk: Fix lightmap calculations somewhat.

Astonishingly, didn't break nor fix any tests. Confounding.
plugin: Remove Exocet dependency.

With this change, plugins should advertise *implementations* of plugins,
instead of *providers*.

I don't know if this is a good thing, but it's certainly a thing!
Move recipes from plugins to policy.

And fix up all of the tests.

This still lets recipes be more-or-less pluggable, while removing them from
the highly dynamic world of plugins.
Move seasons from plugins to policy.

And fix tests, and anybody that references seasons.
plugin: Improve errors and be more stringent in converting plugins.
Convert plugins away from bravo.parameters.

Re-enables and fixes all of their tests.
beta/factory: Hax to get generators to load.
Evict Exocet.

It was fun!