Salt returner to return highstate stats to Librato

To enable this returner the minion will need the Librato client importable on the Python path and the following values configured in the minion or master config.

The Librato python client can be found at:
librato.api_token: abc12345def

This return supports multi-dimension metrics for Librato. To enable support for more metrics, the tags JSON object can be modified to include other tags.

Adding EC2 Tags example: If ec2_tags:region were desired within the tags for multi-dimension. The tags could be modified to include the ec2 tags. Multiple dimensions are added simply by adding more tags to the submission.

pillar_data = __salt__['pillar.raw']()
q.add(, value, tags={'Name': ret['id'],'Region': pillar_data['ec2_tags']['Name']})

Parse the return data and return metrics to Librato.