tags on words and grids
      word should be taggable as "theme" or "obscure" or "roman
      numeral",  and constraints applied via these tags, such as
      limiting the number of obscure words, keeping theme words in the
      correct spaces, and only having no more than one roman numeral
      per puzzle. 

scores for words
       scores should be attached to words, and the filler prefer
       higher scoring words, perhaps searching for the highest scoring
       fill.  The main use of this would be keeping the number of
       obscure words out.

latx output

acrosslite input/output

faster filling (always)

GTK interface

should be able to temporarily remove a word from the solution, and the
solver should change things as little as possible to fix it up.

smarter backtracking

better grid file format (notes, etc)

complete autoconfiscation

randomization of generation (seedable)

optimize backtracking