initial skeleton for vcloud
creation and deletion of vCloud vApps
improved exception handling in vCloud classes
refactored TerraformContext to abstract class
terraform will now fail if an attempt to destroy a vApp fails
polling to determine when vApp has been undeployed before deleting it
VM tasks recorded upon vApp creation
improved atomicity and error handling of vApp creation
refactored common xml building method
removed XOM dependency
parts of credentials can be omitted and passed in as properties
removed unneeded tasks from VMTask