Use is None or is not None for numpy array comparisons.
(#604)
Use direct comparison of _array ptr with 0 rather than let numpy use the overloaded _array != None
(#604)
Change other uses of `== None` or `!= None` to more pythonic `is None`
and `is not None`. (#604)
Add this to the CHANGELOG
(#604)
units problem
clarify meaning of effective diameter
Add more tests of resize to include test of a bug that Josh noticed.  (Currently fails.)
(#604)
Fix an error in how I check for the _array attribute being None in the wrapper code.
(#604)
Fix a bug in the Image dtype when constructed from another image.
(#604)
Add documentation that resize does not perserve the existing data.  (#607)
(#604)
Add new bug fix to CHANGELOG.
(#604)
Fixed typo install instructions pip install startlink
Merge pull request #609 from connolly/master

Fixed tiny typo in install instructions
Update some docs to be more consistent with use of None
(#604)
Regularize the _H header guards and include GalSim_ as a univeral prefix.
Add missing return statement to ChromaticSum.drawImage
clarify demo5 PSF shifts
Merge pull request #605 from GalSim-developers/#604

#604 Change comparisons with None to use `is` or `is not` rather than `==` or `!=`
Merge branch 'master' into #552