poor small chart (PSC)

Copperbox revision 1376.

I've started a new library - Poor Small Chart - for charting on top of wumpus. I've no intention to make the library particularly comprehensive - hence the name. It was going to be Poor Man's Chart, but that didn't seem very inclusive, so I called it Poor Small Chart after the record label PSF. But then I checked on the internet and PSF actually stands for Poor Strong Factory not Poor Small Factory...

I'm going to avoid using wumpus-extra as it is still too much in flux. This may further limit the scope of PSC.