MAINT: use ndarray instead of lists to pass to python functions

Drop custom function PyDoubleArray_AsList().
MAINT: use ndarray for gradient

Drop custom functions PyObject_AsDouble() and PyList_IntoDoubleArray().
TST: separate tests of optimize and tnc (moved to test_tnc.py)
FIX: use PyArray_SimpleNew and memcpy instead of PyArray_SimpleNewFromData in tnc
FIX: don't use PyArray_Type in ParseTuple in tnc
FIX: check the return of PyArray_FROM_OTF in optimize/tnc

To detect invalid types in particular.
FIX: eliminate asarray in tnc python code

Rely on C code for type check and casts
STY: drop docstrings from test_tnc; PEP8
MAINT: drop asarray for gradient in tnc, allow any sequence and check in C
FIX: add missing import_array() in python 3 init of TNC
DOC: typo of 1/sqrt(2), tweak Bessel filter notes
Merge pull request #342 from dlax/tnc-ndarray

ENH: optimize: use ndarrays instead of lists in TNC; separate tests from optimize
Merge pull request #497 from juliantaylor/swig-filetypes

BLD: sparse: add swig filetype headers to sparsetools

setup.py may use these when generating the files
(but this is not enabled in the current build setup)
MAINT: print that we are cythonizing

build logs should always give full information on what is being done
Merge pull request #496 from juliantaylor/print-cythonizing

MAINT: print that we are cythonizing
ENH: special._testutils: add option for accepting nans by default in tests
ENH: special/_testutils: make FuncData accept a comparison functions rather than only taking numerical data
TST: special: add systematic tests against mpmath

This systematically cross-checks values from (nearly) all special
functions that exist both in mpmath and scipy.
ENH: special/_testutils: add an option for ignoring the sign of infinity
TST: special: work around limiting value issues in lpmv & hyp2f1 tests