Merge pull request #427 from paugier/prepare-0.15.1

Add release notes for 0.15.1

Merge pull request #404 from paugier/prepare-0.15.0

Release notes 0.15.0

Merge pull request #391 from gabrielfougeron/nogil_exe_doc

Documented the Cython interface

Release version 0.13.1

tag v0.13.0

tag v0.13.0 release candidate

tag the v0.12.0 release

tag v0.11.1 release

tagging for v0.11.0 release

Merge pull request #126 from hgomersall/master

Fix for all the recent version number breakages. It'll be necessary t…