MAINT: spatial.distance: generate boilerplate with macros
BUG: spatial.distance: fix unchecked malloc
MAINT: spatial.distance: further refactoring

* static on all functions in distance_impl.h
* commented out unused compute_mean_vector
* replaced &&, || with &, | in tight loops
* reindented code according to NumPy conventions
* removed some useless variables
Documented the return value for scipy.signal.find_peaks_cwt
BUG: stats.probplot incorrectly displays the value for R as R^2
MAINT: ignore nosetests coverage files
ENH: sparse: faster setdiag for CSR and CSC matrices
Merge pull request #4103 from larsmans/sparse-setdiag

ENH: sparse: faster setdiag for CSR and CSC matrices
Merge pull request #4097 from akretz/master

BUG: stats.probplot incorrectly displays the value for R as R^2
Merge pull request #4064 from alexeyum/find_peaks_doc

Documented the return value for scipy.signal.find_peaks_cwt
Merge pull request #3948 from larsmans/distance-refactor

Big refactor of spatial.distance