Fix #2559: Make equivalencies work correctly with compose.
Add another compose-to-equivalencies example.
Fix tests
Remove support for Numpy 1.5.x
Reinstate something that shouldn't have been removed.
Re-word CHANGES entry.
Reinstate some of the workarounds for Py3 on io.fits
Added --exact option and fix a little English.
White-space cleanup and more practice.
mention fitsdiff in CHANGES.rst

closes #2782
Further cleanups
Further cleanups
Fix #2889.  Fix #2888.  Fixes deepcopying of SkyCoord.  Makes implicit
attributes immutable.
Add CHANGES.
Fix chaining of Skycoord.__setattr__
Update CHANGES
Test copy more vigorously
Fix unit test
Merge pull request #3100 from mdboom/misc/remove-numpy-15

Remove support for Numpy 1.5
Merge pull request #2888 from mdboom/coordinates/issue2889-2888

deepcopy of SkyCoord fails