Merge pull request #4 from HBOCodeLabs/master

Add "sourceFromPrefix" support to infer the instance name from the metric prefix.
Add the ability to send configured percentile values using the standard statsd config.percentThreshold.  Default to false since it wasn't in previous versions and we want to keep back compat.
Add the ability to auto detect EC2 and GCE instance IDs when the source param is set to detect-aws or detect-gce (source param remains optional).  Thanks to @tvitti-cbtn for inspiration on this in their fork.
update package.json for 0.2.0 release
Merge pull request #1 from Stackdriver/master

Update HBOCodeLabs fork to current Stackdriver master