Added workaround for bug in MacOS X <= 10.8 that caused np.fromfile to fail
Added comment about chunk size
Defer the determination of CHUNKED_FROMFILE until the first time it’s needed
No longer use 2to3 when building astropy. Fixes #2033.
Merge pull request #3083 from astrofrog/workaround-osx-large-fits-reading

Workaround for reading large FITS files on MacOS X
Merge pull request #2033 from astrofrog/no-2to3

Make all astropy code compatible with Python 2 and 3 without requiring 2to3
Added new subpackage. Added Planck function by @skendrew from #1480 and related comments in that PR.
Modified planck function based on the one in pysynphot. Added tests and documentation.