Added totalDuration property to BaseSound class

Author: pavle-goloskokovic

v3/src/sound/BaseSound.js

@@ -90,6 +90,13 @@ var BaseSound = new Class({
          * @property {number} duration
          */
         this.duration = 0;
+        /**
+         * Duration of the entire sound.
+         *
+         * @readonly
+         * @property {number}
+         */
+        this.totalDuration = 0;
         /**
          * Flag indicating if sound is currently playing.
          *