File object support for imread and imsave
MAINT: special: Fix whitespace in cephes/pdtr.c
ENH: special: pdtr and pdtrc give the correct limiting value when m=0.
ENH: special: Return 0 for sufficiently small lambda in pdtrik.
BUG: limit input ranges in special.nctdtr
BUG: return nan when ncp is too large for cdftnc
ENH: signal: Allow upsweeps of frequency in the 'hyperbolic' chirp.

The restriction that f0 > f1 > 0 has been removed.  The only requirement
is that f0 and f1 are not zero.  Negative frequencies can be given.
(Even f0 and f1 with opposite signs are allowed, but this is not expected
to be a useful case.)  The degenerate case with f0 == f1 is now also
handled.

Two small changes not directly related to the above change:
* Changed "geometric" to "logarithmic" in the argument of the ValueError
  that can be raised when method="logaithmic".
* Added `t = asarray(t)` in the function _chirp_phase, so the 't' argument
  of `chirp` is now `array_like`.

Closes gh-3285.
DOC: add note about different ba forms
DOC: clarify `limits` parameter in `winsorize` docstring.
STY: PEP8 the `scipy.stats.mstats.winsorize` function.
DOC: add short explanation to `scipy.stats.mstats.winsorize` doctring.
MAINT: remove unused import
MAINT: remove a usage of np.matrix as a convenience function in newton_cotes
ENH provide a short-circuit for CSR/CSC/BSR sum_duplicates
FIX implementation of has_canonical_format (was is_canonical)
TST: add tests for in-place pchip derivatives

also use consistent naming for derivative order argument
DOC: mention pchip changes in the releases notes
Merge pull request #3331 from ev-br/pch

ENH: interpolate: more pchip changes

Add tests for in-place derivatives (which now work), mention the API changes in the release notes.
Changed parameter naming and added test for file objects
Merge pull request #3271 from jnothman/has_canonical_format

ENH: sparse: provide a short-circuit for CSR/CSC/BSR sum_duplicates

Parallel to has_sorted_indices, this provides is_canonical, allowing sum_duplicates to be avoided in repeated operations.
DOC: special: reformat special function ufunc docstrings + clean them up a bit
BUG: special: escape backslashes in docstrings