[20180620190730] Singletons and Bug Fixes

Adds the option to create services with singleton: true to stop existing containers before starting new ones on deploy.

  • #2735 abort autoscale when largest service larger than a single instance [@ddollar]
  • #2736 add singleton attribute for services [@ddollar]
  • #2737 correct bad behavior when dockerignore ignored itself [@ddollar]