dillon1000/react

Fix bugs that occur when event responder unmounts during a touch event sequence > This PR adds a test (initially failing) for this case along with a fix for stack and fiber. The stack fix was copied from a Diff submitted by @sema. The fiber fix just required us to stop leaking properties for unmounted views. > Longer term we may want to explicitly invoke a release event listener for a responder just before unmounting it. This PR does not do that.