Remove all references to HybridCluster.
Merge pull request #89 from ClusterHQ/pep8-58

PEP 8 support in relevant public APIs and documentation.

Fixes #58.
Merge pull request #101 from ClusterHQ/fix-travis-100

Fix travis builds.

Fixes #100.
Merge pull request #102 from ClusterHQ/branding-93

Remove all references to HybridCluster.

Fixes #93.
Address review comments.
Merge remote-tracking branch 'refs/remotes/origin/master' into reorganize-docs-99