Overseer now creates an autoscaling group on sync if it doesn't exist
Overseer now creates an autoscaling group on sync if it doesn't exist

This new functionality assumes calling sync means you want the group created
if it doesn't exist.  This commit also stops overseer from exploding when
trying to get differences for an autoscaling group that doesn't exist.  Now it
just reports everything as a difference if the remote group doesn't exist.

brianbianco/rivet,brianbianco/rivet