BUG: optimize: mark constraint violations in cobyla as failed solution
DOC: optimize: approx_fprime missing from documentation
DOC: fix a typo in the special.zetac docs

Also throw in the name for the Hurwitz zeta function.
Merge pull request #2893 from pv/cobyla-cv

BUG: optimize: mark constraint violations in cobyla as failed solution
Merge pull request #2903 from larsmans/doc-approx-fprime

DOC: optimize: approx_fprime missing from documentation
DOC: zeta function, numpy format docstring
ENH: add coverage info with coveralls.io for Travis runs.
BUG: coverage didn't run on Travis, try again.
BUG: next try to fix coverage run.
Merge pull request #2905 from EvgeniBurovski/zeta

DOC: special: fix a typo in the special.zetac docs
MAINT: add .coveragerc file to limit content of .coverage file to scipy.

Also add a Coveralls badge next to the Travis CI one in README.txt
Merge pull request #2907 from rgommers/coverage-dot-io

MAINT: add coverage info with coveralls.io for Travis runs.
DOC: document type of stats.chisquare/power_divergence parameters correctly.

Closes gh-2895.