DOC: integrate: move the quad_explain() text to quad() docstring

There's no real reason to keep the documentation in a different place.
DOC: optimize: reformat show_options + fix links to it

Make show_options look better in HTML, and make the links to it
clickable.
MAINT: expm speedup for small matrices by computing exact one-norm instead of estimating
MAINT: naming typos
ENH: sparse: support out= argument in __numpy_ufunc__

This makes several more Numpy ufunc calls to work.
TST: sparse: add test for ndarray dense in-place ops
Merge pull request #2972 from argriffing/bench-onenormest

ENH: sparse: expm speedup for small matrices, through benchmarked one-norm estimation vs. calculation tradeoffs.

In the current scipy expm implementation, estimation of the 1-norm of
matrix products and powers dominates the computation time for the expm
of small matrices. While for large or sparse matrices this 1-norm can be
estimated using clever tricks that are much faster than exact calculation,
for small matrices it is faster to just multiply them out and compute the
1-norm exactly. This PR does some related benchmarking and adds an
arbitrary threshold below which the 1-norm is computed exactly within
the expm calculation.
MAINT: use numpy functions instead of my worse home-made functions
Merge pull request #2940 from pv/sparse-ufunc-out

ENH: sparse: Add support for out= argument in __numpy_ufunc__
Merge pull request #2977 from argriffing/remove-custom-complex-type-detection

MAINT: sparse: use numpy functions instead of home-made functions
BUG: weave: fix issues with temporary directory usage
TST: weave: fix tests on windows
Merge branch 'weave-security-fix' into master.

Reviewed offline because it was marked CVE.
DOC: add 0.12.1 release notes.
TST: increase test coverage of stats module.
BUG: fix incorrect output from stats.tsem.  Add tests for trimmed stats funcs.
TST: fix non-running tests for stats.itemfreq.

TestCase subclasses don't work with test generators.
TST: fix non-running test for stats.mannwhitneyu.
Merge pull request #2913 from rgommers/stats-coverage

stats.py fixes and test coverage
ENH: prefer XDG_CACHE_HOME for weave catalog cache