Rename module in preparation for splitting out all filtering functionality.
Added to hard lowercasing list.
Version 0.3 release.

 - Moved a lot of the preprocessing into wordfilt.py
 - Better uncapping of first words in sentences.
 - Uncapping of ALL CAPS TEXT.
 - Unit tests for capitalization normer, with its ugly regexes.
 - wordfilt.py can now be run directly on a file to test the
   preprocessing.
Update README for new library/utility wordfilt.py.