pypi: Better install_requires parsing:
pypi: Better install_requires parsing:

* Support multi requirements strings (newline separated)
* Ignore comments
* Ignore empty lines

takluyver/conda-build,sandhujasmine/conda-build,shastings517/conda-build,rmcgibbo/conda-build,ilastik/conda-build,dan-blanchard/conda-build,frol/conda-build,shastings517/conda-build,frol/conda-build,takluyver/conda-build,ilastik/conda-build,mwcraig/conda-build,mwcraig/conda-build,rmcgibbo/conda-build,shastings517/conda-build,takluyver/conda-build,sandhujasmine/conda-build,sandhujasmine/conda-build,ilastik/conda-build,dan-blanchard/conda-build,rmcgibbo/conda-build,frol/conda-build,dan-blanchard/conda-build,mwcraig/conda-build