[openbox] Menu stuff.

[Aaron Gyes]

> * Allow user to set an overlap option type thing in the themes,
>   to specify how much a submenu will overlap its parent menu, here's
>   a screenshot of the idea. http://floam.ascorbic.com/bettermenus.png
> 
> * When you move into a submenu, the item should stay highlighted, so
>   you know where you are. Here's some sexy ascii art showing what I 
>   mean. (#### means highlighted.)

Looks like these two were implemented earlier today in cvs.