BUG: fixing linprog's kwarg order to match docs

The upper bound and equality constraint kwargs were swapped, which means that people following the docstring ordering (and not using keywords) would inadvertently supply the wrong constraints.
Merge pull request #3886 from perimosocordiae/patch-6

BUG: fixing linprog's kwarg order to match docs
BUG: Handle the case where status != 2

The local variable `message` wasn't being set in all cases, causing runtime errors.
Merge pull request #3888 from perimosocordiae/patch-6

BUG: optimize: In _linprog_simplex, handle the case where the status returned by _solve_simplex is not 0 or 2.
DOC: sparse.linalg: Fix lobpcg docstring.

Change the markup of the "Acknowledgements" title from a section heading
to emphasis markers within the "Notes" section.

The docstring standard doesn't include an "Acknowledgements" section,
so including one in a docstring generates a warning when building the
docs, and the section is not included in the HTML output.
Merge pull request #3892 from WarrenWeckesser/doc-lobpcg

DOC: sparse.linalg: Fix lobpcg docstring.
DOC: stats: Remove the trailing '_' from the reference to 'levene'.
DOC: stats: Use a more conventional description of the default value for 'moments' in the continuous distribution docstring.
DOC: stats: Fix a bad indent in the histogram docstring.
DOC: stats: Tweak the layout of the PDF function in the ncf docstring.
DOC: stats: Fix bad indent in the relfreq docstring.
Merge pull request #3894 from WarrenWeckesser/doc-stats

DOC: stats: Assorted docstring edits.
MAINT: Add a 'count_nonzero' function to use with numpy 1.5.1.
ENH: stats: Add Mood's median test.