[AstroPy] Domain transfer

[James Turner]

Hi everyone,

Following AstroPy's fiscal sponsorship agreement, I'm in the
process of transferring the astropy.org domain from my registrar
to NumFOCUS, for safekeeping.

This process reportedly takes ~5 days and can involve DNS down
time when switching to the new registrar's name servers. We
should be completely unaffected, as I temporarily switched our
DNS to a third provider that I have an account with yesterday,
but I expect there will be a bit more maintenance going on by
NumFOCUS during the week, just in case. After the initial
switch-over, I'm expecting Erik to be set up as admin and
continue administering the subdomains as previously.

Remember that you can also access the docs and github here (I'm
not 100% sure whether the first one would still work) in the
unlikely event of any problems:

   http://astropy.github.io
   http://astropy.readthedocs.org/en/stable/
   https://github.com/astropy/astropy

Thanks,

James.