Nahuatl verb templates now nearly complete.

Nahuatl verb now have been fitted with TAM markers. These markers are
morphologically quite complex, and also happen to encode the grammatical
number of the subject (wtf).
There are a few remaining problems with this, mainly spelling errors like
"niquimittaqu" for "niquimittac" (I will see you). It will probably be
necessary to bind some sandhi key at word boundaries.