The usage of numerotated labels for this was becoming severly
confusing.

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...

I broke them when I removed call indirection layers without also
removing usage of BCALL.

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.

Will be useful for assembling binaries for the TRS-80 which can't start
at addr 0.