Merge pull request #11 from woodhull/master

Improved Performance of Petition Selection for Email Delivery
Revert "update to latest version of zendesk for compatibility with rubygems 2.0"

This reverts commit 0c490fc8c8446fd25038236292291f909a58f930.
Added NewRelic instrumentation to workers.
Moved newrelic instrumentation to the end.
Combining resque callbacks (our version of resque does not allow us to define it multiple times).