Allow for horizontal scrolling to support very long names

[cb109]

A User reported this:

There is no ability to scroll sideways in the navigation pane. For users who unusually long file paths we are left guessing which assets we are highlighting.

(see https://cbuelter.wordpress.com/2012/09/24/interactive-file-and-object-renamer)

I don't think a maxscript list supports that, but it could be replaced with some dotNet component which does. A way to resize the UI may also be an option.