BUG: core: fix crash when unpickling data on Py3 under non-latin1 encoding
Merge pull request #4882 from pv/fix-unpickle-latin1-crash

BUG: core: fix crash when unpickling data on Py3 under non-latin1 encoding
ENH: core: add hack enabling unpickling Py2 pickled scalars on Py3 under encoding='latin1'

There is a similar hack in place for arrays, but scalar unpickling was not covered.

Provides a workaround for gh-4879
Merge pull request #4883 from pv/fix-scalar-unpickle-py3

ENH: core: add hack enabling unpickling Py2 pickled scalars on Py3 under encoding='latin1'
BLD: fix build issues with MSVC10 on Windows.  Closes gh-4245.

Note that there are a few similar patches posted to gh-4101 and gh-4245.
Those were all patches to msvc9compiler in Python distutils.
Monkeypatching ``MSVCCompiler.link`` is less easy than this change
to ``config._check_compiler``; effect should be the same.

Also updates the error message shown when initializing MSVC fails.

[ci skip]
Merge pull request #4892 from rgommers/msvc10-fix

BLD: fix build issues with MSVC10 on Windows.  Closes gh-4245.
MAINT: .gitignore += generated umath/loops.h

Commit 494abcf1 (ENH: speed-up minimum, maximum and xor for bool dtype)
reworked numpy/core/src/umath/loops.h to be autogenerated at build time,
but forgot to update .gitignore.

Fix it, so that the now-autogenerated loops.h do not constantly show as
untracked in git status output.
DOC: NPY_ITEM_LISTPICKLE -> NPY_LIST_PICKLE

There is no NPY_ITEM_LISTPICKLE - it was NPY_LIST_PICKLE from the
beginning - from c3551579 (Expand usage of hasobject to be a flag-like
entity keeping track of how the data-type should be used.)

The documentation in the same rst file even uses the correct identifier
later, so it was just a typo/thinko.