This was becoming heavy to manage.

Instead of having wordref point to core word routines, I made them
into word 4 word types. It liberates space into the stable ABI and
should make porting to other arches easier.

I'm also thinking of combining word type with the namelen field
for precious bytes saving, but not now...

This is the first commit I do entirely in VE. It's a habit I'm planning
on taking as it helps a lot to find usability issues.

and renamed it "Core words". Also, reworded the presentation.

This leaves space for xcomp-core which is growing.

This allows us to get rid of the (parse*) indirection.

Also, add word "C!+" and fix PSP leak in FILL.