macOS install steps out of date

[TCY16]

Hi,

I tried installing PyBDSF on my macOS, but the current install method for macOS does not seem to work. The single paragraph mentioning the OS points to a solution that is brief, even for and advanced user, and which is not up to date as the main README file mentions that using python setup.py is no longer supported.

While I'm not an astronomer, (but am helping one install this software), in my experience many of them use macOS so getting this resolved seems useful for a larger group. I am happy to help in any way I can, including testing and writing up a step-by-step guide.

Thanks,
Tom