New PartitionsSpec docs.
fix rabbit serde and add tests; fixes #794
address cr
Merge pull request #793 from metamx/partitions-docs

New PartitionsSpec docs.
one more comment
another test for defaults
fix more things
Merge pull request #795 from metamx/fix-rabbit

Fix rabbit serde and add tests; fixes #794
Merge pull request #5 from metamx/master

merge to local master