agena

This release incorporates repairs to the firehose sink which, subsequent to 0.4.12, was accidentally nerfed. That is, the sink was no longer able to store delivered lines into its queue. This release also updates to serde 0.9, making rust 1.15 the minimum rust version that can build cernan. We have also updated to protobuf 1.2, reducing some of the cloning that goes on around the native protocol source/sink.