Merge pull request #1 from nltk/develop

Syncing forked version of NLTK - alvations
Fix to bug #681
Merge pull request #2 from nltk/develop

Syncing fork with v3.0
Merge pull request #695 from helmanofer/patch-2

Fix to bug #681
Paice's method of evaluating stemming algorithms.
remove redundant initialization
Merge branch 'develop' of https://github.com/nltk/nltk into develop
for the universal tagset, unknown inputs map to 'X' not 'UNK'
Fixed reference to the article

Reference to the original article is now full reference.
Merge pull request #703 from lade/paice

Paice's method of evaluating stemming algorithms.
fixes for Python 3, add copyright, misc stylistic fixes
Pep8 and test skip
BLEU score refactoring.

math.fsum is used to make float sum stable.
More tests.
py26 fix
Merge pull request #706 from dimazest/test_nltk.align.bleu.BLE

BLUE score refactoring and more tests.
fix include path
updates for new book location
fixed incorrect year for last two updates
fix ChangeLog url