As usual I can't test my changes, and seeing as this is a fairly major change, I...

As usual I can't test my changes, and seeing as this is a fairly major change, I hope someone can do the extensive testing required to see if it works.

Among other minor changes, Urrebots now save paths between navnodes, for faster navigation.

This commit presents the saved paths as chat bubble icons across the map, and the bots should say "boo hoo!" if they can't find a saved path, if they work at all that is.

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@968 f962a42d-fe04-0410-a3ab-8c8b0445ebaa