Update to retrofit 1.4.1. Recommend latest okhttp.
Make this 2.1.0.
Use setEndpoint instead of setServer.

- See
https://github.com/square/retrofit/blob/master/CHANGELOG.md#version-140-2014-01-31.
Push version to 3.0.0.

- We introduced incompatible API changes.
Change log for 3.0.0.
Merge branch 'release-3.0.0' into dev