added some basic comments for methods, ability to pull the last response after a request is made (useful for inspecting the html response after a bulk delete or extraction), reset for errors + last response before requests to maintain a consitent state between a request those messages, param to add_object to allow tar / tar.gz / tar archives to be extracted once uploaded, method for bulk deleting objects in a container (currently commented out until I have made a commit and pull request to the rackspace php sdk