Added code to map input text to generated text.

textgen.cljs contains functions which take an input text, break it into
sentences, and generate a snippet of random text for each sentence.
Modified mapping algorithm.

Seed for RNG is the sum of unicode values of the characters in the given
string.
Retrofitted it to generate on change in textarea.

Unfortunately, it doesn't actaully change while you're typing, only when
you register the change by removing focus from the targeted textarea. I'm
not well-versed in Javascript and browsers and the like, so further
research on the best way to get it to register as the user types is
required.