Ensure units are converted correctly between CatTrap & Balkon.
Integrate inline layout!
Unittest & fix abstract layout.
Unittest basic grid sizing.
Draft grid width-sizing code.
Test & fix block layout.
Draft flow layout computation. calc() interpretor & multidirectional text to be added later.
Draft new CatTrap API which hopefully is easier to implement.
Unit test calc() implementation!
Draft public API for CatTrap.