Add 'wipe' option to kill_task methods
Add 'wipe' option to kill_task methods

In order to clean up persistent volumes associated with
containers, we need to pass the 'wipe' param to Marathon.

See: https://mesosphere.github.io/marathon/docs/rest-api.html#delete-v2-apps-appid-tasks

thefactory/marathon-python,thefactory/marathon-python