Feature async response

Hey @jakerella – since I don't have push rights to the appendTo repo used in pull request #156, I pushed to my fork and have opened a new pull request. I have resolved the current merge conflicts, and tests are passing in all versions of jQuery except 1.3.2. It seems `complete` is being fired before waiting for the async response. All the async stuff is still firing for 1.3.2, but its not even waiting for any of the new `finishRequest` to fire either. I looked into a it a bit, but couldn't easily figure it out tonight.