Initial implementation of an nsqd connection.
Re-factor NSQDConnection

* The NSQDConnection class has an Event interface
* The state machine for an nsqd connection has been refactoted out of
NSQDConnection.
* Tests for message unpacking
* Correcting parsing of the timestamp for messages
* Specify package versions for certain dependencies
* Tests for nsqd connection state machine
Fix Travis build

Added bignumber.js package
Defined event names and inFlight accounting fix

* Message class now only supports BACKOFF and RESPOND events
* Message's RESPOND event indicates the type of response (finish,
requeue, or touch)
* NSQDConnection decrements inFlight for both finish and requeue
message events.
* Removed discard. Discard logic will be in the Reader.
*
Fixes for CoffeeScript styleguide issues
Merge pull request #2 from dudleycarr/nsqdconnection

Nsqdconnection