Change the keyboard arrow interaction

[ianchanning]

I really wish the arrow key interaction with the outliner structure mirrored the Windows Explorer folder interaction.

• On a parent outline - right arrow opens the children
• On a parent outline - left arrow closes the children (if they're open)
• If a parent is open - down arrow goes to first child not to the next parent
• On a child - left arrow goes to the parent
• On the first child - up arrow goes to the parent

This form of interaction means you can do all moving around and collapsing / uncollapsing of the tree with only the arrows. It means you don't have to learn any Ctrl + combos. Its making use of one of the fundamental features of the windows so will be familiar to most people already.

Currently in edit mode, pressing up when on a child goes to the parent, but if you're in outline mode then pressing up when you're on the first child doesn't do anything. You have to press left.