Firefox won't draw SVGs to a canvas correctly without width/height
attributes (even if a viewBox is present). This commit inserts those
values where needed and removes the Firefox check from the click
detection code, so it works properly (and screenshots are fixed, too).

I wanted to project a land and ocean map together, but that didn't give me filled-in oceans. Will
look at this again at some point.

Also remove a spurious info file for countries

This also updates the attribution system so that entire folders can be covered
by a single entry. It assumes every file has the same source.

units