Merge pull request pusher#160 from pusher/release-3.0.0

Release 3.0.0

Merge pull request pusher#151 from pusher/v214

v2.1.4 release

Merge pull request pusher#139 from pusher/v313

Version 3.1.3 release

release 2.1.2 (pusher#134)

version 2.1.1 release

version 2.1.0 release

1.7.4