Pairwise string alignment in Python

My contribution will be:
 * Code cleanup
 * Support of arbitrary alphabets of input strings (no similarity matrix)
 * Support of both variants:
   1. Smith-Waterman = local alignment
   2. Needleman-Wunsch = global alignment
 
Original Smith-Waterman implementation in Python was forked from
http://narnia.cs.ttu.edu/drupal/node/104
by Forrest Sheng Bao http://fsbao.net
a free software licensed under GNU General Public License (GPL)

A copy of GPL version 3 has been placed into the file LICENSE.