source and destination files for differences since Windows (and probably
other platforms) doesn't set the file modification time to the precise
time requested. Don't notify the observer when we're finished downloading
all files until we've finished all of our work with the file. Check the
return value from the call to setLastModified().
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1598 542714f4-19e9-0310-aa3c-eee0fc999fb1
Walter Korman