Contrib directory with full ubuntu setup code, and 2 scripts

This adds a contrib directory, that shows how to setup a sensu server & client.  That code is in example.

It also has 2 scripts.  

sensu-report (motd) is by @solarkennedy .  It allows for seeing the current state of alerts on motd.
I've added a puppet manifest for ubuntu/ debian boxes that use UpdateMotd, to give real time updates.

sensu-delete (delete_on_shutdown) is for removing hosts from sensu on shutdown. This is *very* handy on AWS.  Autoscaling no longer produces pager / email floods.