unbundle six
build an optional gensim_addons-package
if Cython is present during installation
fix incorrect indent
fix typo in Text8Corpus
make travis CI logs less verbose
fix header paths for Cython
Merge pull request #1 from piskvorky/cythonize_setup

various fixes
Merge remote-tracking branch 'besser82/cythonize_setup' into develop

Conflicts:
	.travis.yml