Remove distribute dependency that is breaking PIP

There's no need to reference the distribute as requirement since the setup.py will not work anyway without it. It's breaking my virtualenv's pip with this message:

zipimport.ZipImportError: bad local file header in ~/.virtualenvs/loremipsum/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg

Without the requirement, it installs ok.