update.sh: fix content URL

Not that the file extension seemed to matter, it's better to be correct.
add note on non-realtime nature of this mirror
Automatic commit for Sat Apr 20 15:20:01 BST 2013
Automatic commit for Sat Apr 20 15:30:02 BST 2013
Automatic commit for Sat Apr 20 15:40:02 BST 2013
indent XML before committing

This makes the diffs a little more readable
Automatic commit for Sat Apr 20 15:42:19 BST 2013
make output from HTML tidy a little quieter
README.md: add note on re-indentation
Automatic commit for Sat Apr 20 15:50:02 BST 2013
add non-planned events to mirroring script
Automatic commit for Sat Apr 20 15:51:44 BST 2013
add future event mirroring
update.sh: add TrafficData product
Automatic commit for Sat Apr 20 15:54:26 BST 2013
update.sh: add back in metadata - might as well

It's only small and it might be of interest
Automatic commit for Sat Apr 20 16:00:16 BST 2013
Automatic commit for Sat Apr 20 16:10:16 BST 2013