Rebase of Hvy Metal I final version

Straightforward forward port.  Drop the code to reset track on
startup.  It's not necessary, and it breaks linking of empdump.

src/lib/update/finish.c

@@ -87,6 +87,11 @@ finish_sects(int etu)
     /* Wipe it clean */
     memset(g_distptrs, 0, WORLD_SZ() * sizeof(*g_distptrs));
 
+    if (opt_RAILWAYS) {
+	for (n = 0; NULL != (sp = getsectid(n)); n++)
+	    set_railway(sp);
+    }
+
     logerror("delivering...\n");
     /* Do deliveries */
     for (n = 0; NULL != (sp = getsectid(n)); n++) {