Fix versions of Python for OSX
Fix versions of Python for OSX

Nikea/scikit-xray,tacaswell/scikit-beam,Nikea/scikit-xray,scikit-xray/scikit-xray,tacaswell/scikit-xray,tacaswell/scikit-xray,tacaswell/scikit-xray,scikit-xray/scikit-xray,tacaswell/scikit-beam,Nikea/scikit-xray,scikit-xray/scikit-xray,tacaswell/scikit-beam