DOC: fixed correlate docstring.

Replaced correlation formula with corrected version that matches the
numpy implementation. Added comment on possible further different
definitions of correlation. Added examples.
Ensure masked arrays are treated correctly for isclose(..,..,equal_nan=True)
MAINT: update pavement.py for no-2to3.
Fix example plot of Laplace distribution

In the PDF used for the example plot of the Laplace distribution only the location parameter loc instead of the absolute difference between random variable and loc was divided by the scale parameter. For the example at hand this makes no difference as loc is 0 and lambda is 1. For different values, however, the plot makes no sense.
Merge pull request #3919 from nkoep/master

Fix example plot of Laplace distribution
DOC: replaced typeset formulas by pure ASCII equivalents.

Replaced typeset formulas by pure ASCII equivalents. Should now be
easier to read in source files.
DOC: Fix misleading description of random_sample in numpy.random docstring.
BUG: close file-like objects returned by urlopen

Fix `ResourceWarning: unclosed file` on Python 3
Merge pull request #3923 from cgohlke/patch-1

BUG: close file-like objects returned by urlopen
MAINT: add NPY_CPU_HAVE_UNALIGNED_ACCESS macro

currently only i386 and amd64, must be used carefully as the compiler
may still be allowed to assume alignment and try to vectorize based on
type size alignment.
Merge pull request #3914 from mhvk/numeric/isclose-mask-safe

BUG Masked arrays treated incorrectly in isclose(..,..,equal_nan=True)
BUG: cov/corrcoef complex input and empty arrays

This preserves the complex (and higher precision float or
object) type of the input array, so that the complex
covariance and correlation coefficients can be calculated.

It also fixes the the behaviour of empty arrays. These will
now either result in a 0x0 result, or a NxN result filled
with NaNs.

A warning is now issued when ddof is too large and the factor
set to 0 so that in this case the result is always NaN or
infinity/negative infinity and never a negative number.

Closes gh-597 and gh-2680
Closes gh-3882 (original pull request)
added spaces to literal string concats

literal string concatination without spaces not
allowed in C++11 anymore
BUG: fix declaration-after-statement

closes gh-3930
MAINT: Define NPY_NO_DEPRECATED_API in struct_ufunc_test.c.src

Removes a compile warning and makes the function use proper macro
replacements. Also fix a pointer type mismatch warning.
Merge pull request #3932 from juliantaylor/windows-annoyance

BUG: fix declaration-after-statement
Merge pull request #3929 from chrodan/strc++11

add spaces to literal string concatination for C++11 compatibility
MAINT: silence warning by casting to right type
MAINT: add npy_memchr for memchr like operations

useful for small sizes where the function call is expensive.
Merge pull request #3913 from bspinnler/fix_correlate_docstring

DOC: fixed correlate docstring.