pip install does not install requirements

[davidedelvento]

And if image_registration is installed on a clear slate, it fails by not finding (e.g.) matplotlib and pytest (which as mentioned in #16 should be made optional, even though I'm fine with them being required)

[keflavich]

The installation requirements are specified in setup.cfg. I added matplotlib here: 8df26a7. pytest... shouldn't be required to load image_registration? If it is, again, that should be factored out.

[keflavich]

ok, I see pytest is also incorrectly required. Thanks for noting that.

[keflavich]

fixed pytest requirement in a47d247. It can't easily be factored out; @pytest.mark is needed at import time.

[davidedelvento]

Sounds good. The bug report was based on the version published on PyPI, perhaps that was released before 8df26a7?