new charm: sensu-agent

Hi Paul! Thanks for this submission as well. I'm starting the review process now.

Thanks you again for your patience, I know you have a few charms still waiting and we're working on getting to them.

First, the output of `juju charm proof` from charm-tools shows the following:

W: No icon.svg file.
W: config.yaml: option rabbit_host does not have the keys: default
W: config.yaml: option rabbit_password does not have the keys: default

Like with sensu-agent we now request that authors include icons for all charms. Instructions on this are available on our docs https://juju.ubuntu.com/docs/authors-charm-icon.html

You'll find the majority of feedback from https://bugs.launchpad.net/charms/+bug/1236112/comments/2 applies. Key points, use $JUJU_REMOTE_UNIT in lieu of hostname as it'll better describe what service it's monitoring.

Let us know if you have any questions. You can reply to this thread, post to the mailing list <email address hidden>, find us in #juju on freenode.net, or ask a question on http://askubuntu.com

I've moved this to incomplete, when ready for another review please move to either "fix committed" or "new". Thanks again for your hard work so far!