Allow ajax loaded blocks to be reloaded on the same page

One feature I'd like to add is the ability reload the ajax blocks on certain events, however when the blocks are loaded the first time, the HTML id used to identify the placeholder is removed when the real content is placed into the document.

Simply, if the id is placed back in the same place relative to the wrapper then that allows other scripts to trigger the blocks to reload as they please. This patch allows this to happen.