Added Object::scale() for scaling proportionally in all dimensions.

src/Object.h

@@ -153,6 +153,15 @@ class MAGNUM_EXPORT Object {
             scale(Vector3(x, y, z), global);
         }
 
+        /**
+         * @copydoc scale(Vector3, bool)
+         *
+         * Scales the object proportionally in all dimensions.
+         */
+        inline void scale(GLfloat xyz, bool global = true) {
+            scale({xyz, xyz, xyz}, global);
+        }
+
         /**
          * @brief Rotate object
          *