DOC: tf2ss zpk2ss note controller canonical form

There is only one way to convert from state space form to transfer function, but there are multiple state space forms for a given transfer function.  (I'm trusting that the comment in tf2ss accurately describes the code.  This is what Matlab does too.)
BUG: fix weave issue with too long file names with MSVC.  Closes gh-3216.

This issue was introduced in 021e0ee15.  It's MSVC specific; MSVC
has a 260 char file name (including full path).  So truncation the
has to 50 chars, plus filename prefix (``sc_`` or ``compiler_``), leaves
200 chars for the path which should be enough.
DOC: Add See Also links for *ord functions
DOC: Add examples with plots for filter design functions
illustrating how the passband and stopband specs constrain the filter frequency response
Fix typo in warning
Merge pull request #3228 from endolith/patch-6

DOC: tf2ss zpk2ss note controller canonical form
DOC: Fix comma typo and missing example namespaces
Merge pull request #3234 from endolith/patch-3

Add See Also links and Example graphs to filter design *ord functions
correct doc for pchip interpolation
DOC: fix ReST errors in the BPoly docstring

[ci skip]
Merge pull request #3240 from ev-br/bpoly_docs

DOC: fix ReST errors in the BPoly docstring
RF: check write attr of fileobject without writing

I was checking whether passed file object could write by doing a write
of an empty string. Writing an empty string can fail for bz2 objects in
python 3.3:

http://bugs.python.org/issue16828

In any case, testing that 'write' is callable with an empty string is
asking too much of the interface. Instead just check if the object has a
'write' attribute.
BUG io: fix file descriptor closing for netcdf variables

File descriptors created for each Variable stayed open when
using mmap

Closes gh-1555
TST: add regression test for gh-1550 (netcdf_file leaves mmaps open).
Merge branch 'pr/2792' into master.

Reviewed as https://github.com/scipy/scipy/pull/2792
Merge pull request #3232 from rgommers/weave-msvc-fix

BUG: fix weave issue with too long file names with MSVC.  Closes gh-3216...
MAINT: update scipy-sphinx-theme
Merge pull request #3239 from bmcage/monohermspline

DOC: interpolate: correct doc for pchip interpolation
Merge pull request #3241 from matthew-brett/relax-mio-write-check

BUG: io/matlab: check write attr of fileobject without writing