ENH: interpolate: add the rescale argument to griddata and NearestNDInterpolator

When it was added to the linear and cubic nd interpolators, the
nearest-neighbor one and griddata() were missed.

Also, refactor NDInterpolatorBase to avoid some work that is unnecessary
in the nearest neighbor interpolator.
hyp1f1: evaluate ratio of gammas via log(gamma)
DOC:Add freqz magnitude plotting example

Mention a callable that produces the expected plot
Added 'wrap' as a vaild mode for savgol_filter.
minor documentation/error message corrections

added trivial + simple tests
DOC: Fix backtick mistake, add plot callable note to freqs() also
Merge pull request #3042 from endolith/patch-2

DOC: signal: Add freqz magnitude plotting example
Merge pull request #3019 from gertingold/gh-2957

BUG: special/hyp1f1: evaluate ratio of gammas via log(gamma)
Merge pull request #3045 from tacaswell/savgol_wrap

Added 'wrap' as a vaild mode for savgol_filter.
BUG: optimize: include Result in main namespace
BUG: fix bug in mstats.kurtosistest

Deleted astype(), because it is not an attribute of int (which could
be returned instead of an ndarray).
BUG: fix several bugs in the mstats normality tests.

Also provide decent test coverage.
TST: clean up test_mstats_basic.py for docstrings in tests
BUG: fix errors in mstats.ttest_rel and mstats.ttest_ind.

Change default of axis kw to 0 in ttest_rel.  This is OK without warning
because the function didn't work before anyway.

Also provide basic test coverage (comparison against nonmasked version).
Testing with various masked array inputs to be done.

Closes gh-3047.
BUG: fix issues in mstats.ttest_1samp.  Add axis keyword.
TST: normality tests: add a couple of tests for stats vs mstats
Merge pull request #3008 from rgommers/pull-2673

Fix mstats.kurtosistest, and test coverage for skewtest/normaltest
quick hack for fast CSC hstacking
ENH: adding fast-path for compressed hstack/vstack
using @pv's suggestion for more speed