They are now generated by a build.rs script from nothing but the
colorspace's primaries, which makes it super easy to add more
colorspaces. So easy that I added three more: ACES AP0, ACES AP1
and Rec.2020.
This lays the foundation for supporting output to different
colorspaces.
Also created a proper World struct in the process, to store all
infinite-extent type stuff.
Note that I goofed and did a new rustfmt pass but forgot to
commit before making these changes, so there's a lot of
formatting changes in this too. *sigh*
