By TravisCarden: Replaced hook_shunt_enable() and hook_shunt_disable() with hook_shunt_post_change() and added hook_shunt_post_changeset().
By TravisCarden: Added new "Administer shunts" permission.
By TravisCarden: Added Drush shunt name completion.
By TravisCarden: Added shunt definition validation and sanitization.
By TravisCarden: Added ability for shunt-enable and shunt-disable Drush commands to accept multiple shunts.