Update jerryscript each frame.

src/dusk/script/script.h

@@ -22,6 +22,14 @@ extern script_t SCRIPT;
  */
 errorret_t scriptInit(void);
 
+/**
+ * Updates the script system, running any pending jobs. This should be called
+ * once per frame.
+ *
+ * @return Any error that occurred.
+ */
+errorret_t scriptUpdate(void);
+
 /**
  * Evaluates a JS source string in the global scope.
  *