Saving in ../css/ for better directory structure

Added functionality to save in ../css/ instead of the working directory,
so that when working with /x/less and /x/css structure, you can use this
extension too...

Added a menu item "[BracketLESS] Save in ../css/" and used same structure for injecting it. Added a if that checks if enabled and then replace "/less/" with "/css/" in the css saving path.