Add MalletCorpus format
Merge pull request #179 from cscorley/malletcorpus

Add MalletCorpus format
use smart_open in all corpora (allowing compressed I/O)
add corpus (de)compression changes to CHANGELOG
add python 2.6 to travis CI
add dates to CHANGELOG
simplify banner
minor doc fixes
bump version to 0.9.0
remove tox file (uses travis CI now)
re. #172: update docs for word2vec fvocab
add download badge from pypin
add license badge from pypin
update README
update LdaMallet docs
prevent unclosed file warning from Python 3
fix broken relative import in Python 3

Verified that tests still pass in Python 2.7.
Fix CBOW bug (optimization 2)
Various Python 3 fixes

Test results now failures=4, errors=10
Down from        failures=5, errors=68

Not counting testLineSentenceWorksWithCompressedFile from word2vec
tests, which ends up in what seems to be an infinite loop.
Merge pull request #181 from sebastien-j/cbow_minor_bug_fix

Fix CBOW bug (optimization 2)