reset() {
    // Clear the stack.
    this.stack = [];

    // Restore stackOffset to its original value.
    this.stackOffset = -1;

    // Clear the editable area.
    this.$editable.html('');

    // Record our first snapshot (of nothing).
    this.recordUndo();
  }
@method reset
Resets the history stack completely; reverting to an empty editor.