Remember which file a session was opened from, so it can be the default one

[u/mdw/putty] / website.url

[InternetShortcut]\r
URL=http://www.chiark.greenend.org.uk/~sgtatham/putty/\r
\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0