Menus, control settings

The style change on the menu is mostly because I wanted to show what the currently selected entry is without changing the text color and taking up little additional space. It can be changed easily enough.
I tried to make `menu` basic and flexible enough to be used for many things. Say, we show character stats when an item is selected, displaying increased ones in green and decreased in red.

I don't know what kind of controls we're gonna support, but I added mouse input to menus, because why not.