Include "Go up" extension for better integration

[Kristoffer Lundén]

The extension "Go up" for Firefox provides an "Up" button plus the shortcut ALT+uparrow for navigating upwards in a url hierarchy, where "example.org/foo/somepage.html" becomes "example.org/foo/" and so on.

This is exactly the same behaviour as Nautilus and Epiphany both has, down to the shortcut used. Not to mention that it's a really useful function.

As long as Firefox is the default browser, we shouldn't be missing out on this excellent functionality. Plus it would mean a more coherent desktop. =)

https://addons.mozilla.org/extensions/moreinfo.php?id=1677&application=firefox

Should be preinstalled, and Up button placed in toolbar next to Forward.

Tested and it works really well in latest Dapper with Firefox 1.5 (also latest in repos).