Sort-of implement cube and cylinder and sub{} with pythonocc, so simple.ycad works.
Support move() and rotate() with pythonocc.
Support add{} and mul{} with pythonocc.
Support scale().
Make make() a no-op for empty combinations.
Refactor withTransform() to withTransform() and applyTransform().
Implement cylinder(center=).
Implement sphere().
Raise a NotImplementedError for polyhedron().
Remove old references to wdb.
Fix rotate() to accept degrees instead of radians.
Remove brlcad dir.
Rename BrlCadObject to Object3D.
Use wraps() decorator when wrapping Python functions, so built-ins should work again.
Wrap entire program in a Program statement, wrap this and parsing in
general in a new grammar.parseFile() function.
Allow functions to accept a block as a parameter (like Ruby?);
re-implement csg as block functions.

This means no csgExpr, so mathExpr is now just expr.
When running a script that generates no geometry, just create an empty STL file.
Remove asRegion combination parameter.
Add move, scale, rotate block functions.
Change lots of '+'s to '-'s in grammar, so error locations are clearer.
(and maybe grammar will be a tiny bit faster)