Undeploy Tomcat tasks should allow for failure to be ignored

I wanted to make a request for the Tomcat Undeploy task to have an optional "Ignore Undeploy Failure" feature so that if the webapp fails to undeploy it won't fail the build.

This would be immensely helpful in situations where you're deploying to a Tomcat server for the first time, or the last deployment failed for some reason and you want to re-run the deployment job without having to remember to go in and disable the Undeploy task.

An alternative would be a totally new task called something like, "Conditionally Undeploy" which only undeploys if there's a web app deployed at the given context root.