implement a word compare filter for drawit that filters non-alphanumeric (\W) characters and words ending in "s" (s$) and "ing" (ing$)

it's easy to do and will correct a lot of irksome errors that people have no real control over

using a very big sample size, the -s and -ing filters shouldn't affect any words. even words like gas (->ga) and spring (->spr) won't be confused with their counterparts gag/gap/gat or sprint/spritz/sprite