Configurable keyboard shortcuts.

For some stories with long content, I need to scroll within a single story. I prefer to do this with the arrow keys, as this is how every other application everywhere behaves. But since up/down arrows are bound to prev/next, I frequently jump to the next story instead of scrolling the current one.

Every user is going to want slightly different behaviors, so configurable keybindings would let everybody set things the way they want.