Pep8
Moved deployment code to WebsiteDeployment class
Refactored prune_obsolete_instances
Make it possible to deploy the same git commit hash multiple times
get_instance_stamp: handle duplicate deployment
Restored restart message
get_instance_stamp: handle missing link
backup_and_download_database: use tmp directory for backup
Added before_collect_static_files hook
Added create_symbolic_links option
Merge commit '3935ee8a99f88f772719a2e3e5569c7759a300cd' into puppet
Added an option for non-interactive deploys