An unknown port (look at amounts, not percent).

I've seen some ports that have 0 percent, but a few values
in amounts.  (It's a valid state for a port, really!)

galaxy.cpp

@@ -28,7 +28,7 @@ std::ostream &operator<<(std::ostream &os, const port &p) {
 
 bool port::unknown(void) {
   for (int x = 0; x < 3; ++x) {
-    if (percent[x] != 0) return false;
+    if (amount[x] != 0) return false;
   }
   return true;
 }