Support annotations

[lf94]

See raylib draw3d examples that use text.

Annotations are not part of the SDF mesh. They must be attached to libfiveValues and stepped over in the preview function.

It's gonna be kinda complex.

An annotation function should take a start and end point (line start, end), and text that will be centered above it.

~~Depends on https://github.com/lf94/summonscript/issues/1~~