Fix VMM.Library.prop and VMM.Library.attribute

prop() previously had a version check for jQuery’s prop()
function which failed, causing it to never return values for
e.g. scrollHeight.

attribute() previously always hit the setter path because it
didn’t check for value being undefined so it always called
jQuery using the two argument form.

source/js/Core/Core/VMM.Library.js

@@ -282,21 +282,20 @@ if(typeof VMM != 'undefined') {
 		},
 
 		prop: function(element, aName, value) {
-			if (typeof jQuery == 'undefined' || !/[1-9]\.[3-9].[1-9]/.test(jQuery.fn.jquery)) {
-			    VMM.Lib.attribute(element, aName, value);
+			if (typeof jQuery == 'undefined' || !('prop' in jQuery.fn)) {
+			    return VMM.Lib.attribute(element, aName, value);
+			} else if (typeof value != 'undefined') {
+				return jQuery(element).prop(aName, value);
 			} else {
-				jQuery(element).prop(aName, value);
+				return jQuery(element).prop(aName);
 			}
 		},
 
 		attribute: function(element, aName, value) {
-			
-			if (value != null && value != "") {
 			if (typeof(jQuery) != 'undefined') {
-					jQuery(element).attr(aName, value);
-				}
+				if (typeof(value) != 'undefined' && value != null && value != "") {
+					return jQuery(element).attr(aName, value);
 				} else {
-				if( typeof( jQuery ) != 'undefined' ){
 					return jQuery(element).attr(aName);
 				}
 			}