MAINT: fitpack: trim down compiler warnings (unused labels, variables)
BUG: make matlab happy with empty sparse arrays

Closes gh-4208
TST: add test for empty sparse matrix write

Check that writing empty sparse uses max nnz of 1.
BUG: sparse: work around alignment issue in f2py in Numpy 1.9.1

This version of Numpy specifies complex dtype alignments that are not
guaranteed by system malloc on win32, so that np.zeros does not produce
sufficiently aligned arrays.

Work around this issue by using an aligned allocator for intent(inout)
arrays that are potentially complex valued.
Merge pull request #4212 from matthew-brett/test-sparse-patch

MRG:fix for gh-4208
Merge pull request #4241 from pv/f2py-aligned-alloc

BUG: sparse: work around alignment issue in f2py in Numpy 1.9.1
Merge pull request #4116 from ev-br/fitpack_warns

MAINT: fitpack: trim down compiler warnings (unused labels, variables)
ENH: spatial: add query_subset to KDTree (#4236)