Add vision sanity checking, fix more vision

- Add a vision sanity checking routine

- Recalc block point when digging a door for temporary clouds

- Add recalc_block_point after cvt_sdoor_to_door, because doorways
  on the Rogue level have no doors, and otherwise the sanity checking
  would complain.  This doesn't actually change how the Rogue level
  vision works, as it uses a different vision system

- Monster using a trap in a secret corridor revealed the corridor,
  but didn't unblock the vision unless you saw the location

src/read.c

@@ -2035,8 +2035,11 @@ seffect_magic_mapping(struct obj **sobjp)
 
             for (x = 1; x < COLNO; x++)
                 for (y = 0; y < ROWNO; y++)
-                    if (levl[x][y].typ == SDOOR)
+                    if (levl[x][y].typ == SDOOR) {
                         cvt_sdoor_to_door(&levl[x][y]);
+                        if (Is_rogue_level(&u.uz))
+                            unblock_point(x, y);
+                    }
             /* do_mapping() already reveals secret passages */
         }
         gk.known = TRUE;