Fix release of CatTrap 0.4 (as I should've called it...)

Test table lowering

Improve concurrency, release 0.3, & (not in 0.3) better expose text info

Describe remaining submodules.

Reference-document grid layout.

Refactor grid layout code to deduplicate logic along each axis.

Tidyup: full-size computation from gridcell size computations.

Refactor grid sizes to be dynamically computed.

Merge branch 'main' of git.argonaut-constellation.org:~alcinnz/CatTrap into main

Define public APIs.

Draft grid preprocessor which sucessfully compiles.

Unittest & fix abstract layout.

Unittest basic grid sizing.

Build testable gridlayout function, fix syntax errors.

Finish drafting CSS4 Grid support!

Draft grid width-sizing code.

Test & fix block layout.

Draft new CatTrap API which hopefully is easier to implement.

Unit test calc() implementation!

Draft public API for CatTrap.