ENH support getting single element from CSR/CSC where duplicates are present
TST fix skipping for non-canonical sparse tests
STY refactor inequalities for CSR/C

Otherwise, the differences are difficult to spot
BUG comparison operators for non-canonical compressed sparse matrices
Merge pull request #442 from pv/ticket/1307

ENH: sparse: enable 64-bit index arrays & nnz > 2**31
Merge pull request #3245 from ev-br/frozen_distr

BUG/ENH: stats: make frozen distributions hold separate instances
TST: signal: add some tests for fftconvolve padding
Merge pull request #3144 from endolith/smooth_fft

ENH: Speed up fftconvolve by using 5-smooth length to pad FFT

The speed of fftconvolve can be improved by choosing the padding more
carefully --- it's not necessary to use exactly power of 2, since
FFTPACK does handle also composite numbers of 2, 3, and 5.
BUG+TST: setdiag implementation for dia_matrix (Close #2931) + test_setdiag (was untested)

Revealed similar lack of setdiag imlementation for COO and BSR matrices (TODO)
TST: mark test_setdiag for BSR and COO as a known failure
enable setdiag for non pre-existing offsets
Fixing off-diag impl, adding test case.
Workaround format hack.
BUG: sparse: preserve offsets dtype in setdiag
Merge pull request #2932 from pr-2932

BUG: sparse: setdiag implementation for dia_matrix
DOC: fix see also and examples in filter design docstrings.

- see also lists cannot also have descriptions
- examples need namespace for pi -> np.pi
TST: signal: add strict check for _next_regular
BUG: updated signal.buttord to be consistent with other filter design methods.

It now optimizes the order and natural frequencies such that the passband
is just met while maximizing the stopband (or vice versa for stopband filter).
TST: updated butterworth filter tests for update to signal.buttord function.

Also tightened tolerance to 1e-6 on butterworth test_bandstop.
Merge branch 'pr-3235' into master.

Reviewed at https://github.com/scipy/scipy/pull/3235