Show key equivalent in window title.

Show key equivalent in window title, so the shortcut is obvious at a glance.

By default, this is disabled. To enable it, set the new wm_show_shortcut default to true.

--Tom

![key_equivalents](https://cloud.githubusercontent.com/assets/1269020/5081236/69df5c64-6ec4-11e4-8070-6757126c8f75.jpg)