Bugfix: Make sure we wait until 'count' servers have launched in the Launch actor.

The rightscale.server_array.Launch actor optionally takes a 'count' of
servers to launch -- but when it comes time to monitor how many servers
are running, it was only looking at the ServerArray 'min_count' rather
than actually paying attention to the count supplied by the user.
Bump versino
Merge branch 'master' of github.com:Nextdoor/kingpin into fix_launch_actor_with_specific_count
Replace use of self._options with self.option()
Merge pull request #104 from Nextdoor/fix_launch_actor_with_specific_count

Fix launch actor with specific count