BUG: Fix various problems with the np.ma.masked constant#9336

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charris merged 8 commits intonumpy:masterfrom

eric-wieser:masked-constant

Sep 21, 2017

Commits on Jul 16, 2017

MAINT: Improve comments and tests, in response to review
eric-wieser
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Commits on Jul 18, 2017

Commits on Sep 13, 2017

DOC: Add release notes warning about np.ma.masked immutability
eric-wieser
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