Generalized ajax behavior into a menu factory. This makes it possible
for the user to specify a function tht will create submenus (given the
'op' and menuName).

Add 'menuFetcher' to your options list and supply a function that takes
three parameters.

Here is the default version, which is just the current ajax fetch.


			menuFetcher: function(op, m, callback){
				$.ajax({
					type: "POST",
					url: op.options.template,
					cache: false,
					async: false,
					data:"menuId="+m+(op.options.additionalData!=""?"&"+op.options.additionalData:""),
					dataType:"html",
					success: callback
				});
			}

			I found this useful when mbmenu is used with angularjs,
			because often it is required to 'compile' some html into a
			menu.