KLV streams can now pass through as well as duplex

Made passing through the data (re-emitting it) an option so the KLV
stream can be used in duplex or as a through pipe
Fixed emitData bug

Fixed a bug with emitData breaking when no options are provided; now
only works with Node v0.8 and above
Merge pull request #6 from mjohnsullivan/master

Updated streams for optional passthrough