Release v0.5.0

Mostly bug fixes but changes to reconnection logic so bumping to major version:

• Fixes to publish_request API which was not calling flushing like publish (#16)
• Fixes to max_reconnect_attempts to enable infinite reconnects by setting it to -1 (#17)
• Fixes to stopping of ping interval on disconnections (#12)
• Added reconnect_time_wait to set the time to back off before trying to reconnect to a server (#17)

https://pypi.python.org/pypi/nats-client/0.5.0