readme: use SVG for travis img
readme: move travis img
nsqd: don't attempt to decode buffers smaller than the minimum
nsqd: add #ephemeral topics
Merge pull request #461 from mreiferson/panic_461

nsqd: panic on decoding invalid message data
Merge pull request #305 from mreiferson/ephemeral_topics_305

nsqd: ephemeral topics