Added t4162 - test using sub/%O as an output.

The subdirectories were only being created when parsing 'sub/%O', so if '%O' expanded to something with a '/' in it, then tup would add an entry in the database for a filename with a '/' in it rather than creating another level of directories.

Fixes #162.
Update file headers to 2014.

Updating it on a per-file basis was annoying.