Break out "extras"

[razterizer]

Features that are not the bare minimum should be moved to "extras" repos, such as Termin8or-extras-ui and Termin8or-exras-physics etc...
Then add submodules to Termin8or so you can have a smorgosboard of feature sets to choose from. Extras must be separable from each other of course.

[razterizer]

Perhaps not necessary. After all, this is just a header-only repo. Maybe suffices to have a better folder structure.

[razterizer]

I think my former comment was less informed. I think we do need to break it up. However it is quite tricky. Perhaps a dry run first?