added skyline metrics handler
removed trailing whitespace
Updated skyline.rb header

Updated header per Sensu contributor guidelines [https://github.com/sensu/sensu-community-plugins/blob/master/CONTRIB.md]
Update skyline.rb

removed trailing whitespace
Merge pull request #889 from tracyde/master

Added a metrics handler that feeds data into Etsy's Skyline server (https://github.com/etsy/skyline)