ENH: scipy.special information theory functions
TST: remove negative inputs
BUG: cluster.linkage array conversion to double dtype
Sort netcdf variables in a Python-3 compatible way

The previous implementation ran into issues with comparing different
types (tuples and bools).

Also simplified the sorting, since Python 2.3 support is no longer an
issue.
Add test for zero dimensional netCDF variables
Ensure isrec always returns a boolean
Placate irritating pep8 checker
TST: adding test cases for COO sum_duplicates
ENH: adding sum_duplicates method to COO matrix
Fix for #3596: Make fftconvolve threadsafe
adding has_canonical_format to COO matrix
fixing build errors
incorporating @jaimefrio's vectorized version
Consolidate duplicated code in fftconvolve
Fix small typo in comment
ENH: Added support for date attributes to io.arff.arffread

Requires numpy >= 1.7
Throw exception of date attribute contains time zone information

Updated unit tests
Skip datetime tests if numpy < 1.7.0
Skip setUp when numpy < 1.7.0
ENH: Small speedup of FFT size check

Use a bit-twiddling power of 2 check instead of repeatedly dividing by 2