reorganise alignment code, incorporate Thorsten Marek's port of Gale-Church
brought in implementations of IBM Models 1-3
import fixes
fixed min()
code style fixes
fixed gale church implementation so doctests work; used log probabilities instead of raw probabilities for the distance function to improve accuracy
Merge pull request #562 from jskda/align

Fixes to the align branch
Merge branch 'develop' into align
Merge branch 'pull_request.505' of https://github.com/jskda/nltk into align
Updates doctests to use fromstring() method instead of read().
Merge pull request #666 from Liechti/develop

Updates doctests to use fromstring() method instead of read().
Doctest fixes for renaming in commit d566f23 and the read() -> fromstring() change.
Merge pull request #667 from Liechti/develop

Doctest fixes for renaming in d566f23 and more read() -> fromstring() changes
Merge branch 'develop' into align
Merge branch 'align' into develop
Merge branch 'develop' into omw