Anti-aliased relevant menu bar icons

The title says it all - I took the current menu bar images and anti-aliased them with GIMP. I didn't do `senotifier.png`, as that seems to already be anti-aliased.
A comparison between the two in situ can be seen at https://dl.dropbox.com/u/2042276/SENotifier%20Anti-aliased.tiff - the left is the current icon, and the right is my anti-aliased one.