First pass at making arrow rotate

Does not work in Chrome
Make it work with webkit

Stupid prefixes enforcing the hidden WebKit hegemony agenda promulgated by
Google...
Made the map transition too for a v. cool effect

Tested with current versions of IE, Firefox and Chrome. Anything that
doesn't understand transition should just ignore it. (This is also the
case for the transform, worst case the arrow will stop changing for some
where it did before, but damn the torpedoes and steam on ahead! Browsers
will only get more modern.)