check for capistrano-ext and print the stage in notifications
notify on start of deploy with stage
don't blow up if branch isn't specified

we don't have a default branch specified, so the deployment_name
function blows up when it checks for the existence of the `branch`
variable. used fetch to fix that.
Merge pull request #29 from sge-slingshot/multistage-support

Capistrano multi-stage support
Merge branch 'do_not_blow_up_without_branch' of https://github.com/spikegrobstein/hipchat-rb into spikegrobstein-do_not_blow_up_without_branch
Version bump to 0.8.0
Regenerate gemspec for version 0.8.0
Only send notifications if we are not passing the --dry-run (-n) option