setup.py: Load requires from requirements.txt

setup.py

try:
    from pip.req import parse_requirements
except ImportError:
    def requirements(f):
        reqs = open(f, 'r').read().splitlines()
        reqs = [r for r in reqs if not r.strip().startswith('#')]
        return reqs
else:
    def requirements(f):
        install_reqs = parse_requirements(f)
        reqs = [str(r.req) for r in install_reqs]
        return reqs
        
# ...
install_requires = requirements('requirements.txt')