ENH: ma.asarray() and ma.asanyarray() will pass through input of the correct type.

If x is of type MaskedArray for ma.asarray(x) or any subtype of
MaskedArray for ma.asanyarray(x), these functions will simply return x.
This makes them consistent with their numpy counterparts.

Closes gh-4043.
BUG: Fixed mask_rowcols().

Previous implementation relied on ma.asarray() to always create
a new object.

See gh-4043.
ENH: Make output of get_atlas_info conditional on system_info.verbosity
ENH: optimize srcstride0 copy with O3

enables autovectorization with gcc and improves performance by about 25% for cached data.
Merge pull request #4387 from abergeron/get_info

ENH: Make output of get_atlas_info conditional on system_info.verbosity
DOC: Add the change to disutils in the release notes.
Merge pull request #4514 from abergeron/get_info

Add the change to disutils in the release notes.
FIX: missing asarray import in numpy.libs.utils
TST: add unittest for byte_bounds
Merge pull request #4515 from ogrisel/undefined-asarray

FIX: missing asarray import in numpy.libs.utils
BUG: catch overflow of nominator in datetime conversions

closes gh-4486
Merge pull request #4518 from juliantaylor/datetime-overflow

BUG: catch overflow of nominator in datetime conversions
FIX: items/keys iterators in 3k, list wrapping
DOC: Link convolve with polymul

Matlab uses `conv` for both convolution and polynomial multiplication. Clarifying that numpy has functions for each.
ENH, MAINT: Check that covariance is positive-semidefinite.

numpy.random.multivariate_normal uses SVD to obtain the covariance
square root, but the result will be incorrect if the covariance is not
positive-semidefinite and no warning will be given. However, a check can
be made even while using the SVD by checking if the rows of u.T and v
have the same sign, where u and v are given by u, d, v = svd(a).

A deprecation warning is also fixed. When the default size was used an
empty list was passed to multiply.reduce, which resulted in a default
float 1. for a shape index. That is no longer legal. The problem is
fixed by using an array reshape, which also avoids potential overflow in
the original computation.

Closes #4489.
TST: Add some tests for random.multivariate_normal.

Explicitly Test that the default shape does not raise a
DeprecationWarning.

Check that a covariance matrix that is not positive-semidefinite
raises a RuntimeWarning.
DOC: Note new random.multivariate_normal warning in release notes.
Merge pull request #4522 from ninjin/master

FIX: items/keys iterators in 3k, list wrapping
Merge pull request #4490 from charris/fix-random-multivariate-normal

Fix random multivariate normal
Merge pull request #4512 from juliantaylor/opt-srcstride0-copy

ENH: optimize srcstride0 copy with O3