Fixed a few issues from the last commit, also removed the HTML output of used domains when the quota is 'unlimited' as in my opinion there is no need to output  graph/used as the pie graphs are there to give a graphical representation of used/avaliable. As the numeric values of the used and avaliable are printed at the top of the Usage module anyways, I thought it looked cleaner to remove the orphaned HTML. I also fixed up some issues with HTML errors in Usage Viewer module. - Added new Unlimited image too!