17.3.0 release

Prepare 17.2.0 (pyca#671)

* Fix version

* Prepare 17.2.0

17.1.0 release

version

16.2.0 release

16.1.0 release

Merge pull request pyca#454 from hynek/master

Prepare 16.0.0

Merge pull request pyca#228 from hynek/release-0.15.1

Prepare 0.15.1

Merge pull request pyca#220 from hynek/release-15

Release 0.15

Bump version to 0.14 final