rgitools fails to install using pip in environments with newer versions of setuptools, due to a conflict with PEP440:

I was able to fix this by changing changing line 86 from this:
FULLVERSION = rev.lstrip('v').replace(VERSION + '-', VERSION + '+')
to this:
FULLVERSION = rev.lstrip('v').replace(VERSION + '-', VERSION + '+').replace('-', '+', 1)
This fixes the version number error, and rgitools installs as expected:
