Reuse former session of second split. Add destroy function that stops some timeouts.

lib/ace/split.js

@@ -103,6 +103,7 @@ var Split = function(container, theme, splits) {
         } else {
             while (this.$splits > splits) {
                 editor = this.$editors[this.$splits - 1];
+                editor.destroy();
                 this.$container.removeChild(editor.container);
                 this.$editors.pop();
                 this.$splits --;