Added definitions and support for all the various red sandstone blocks.

overviewer_core/src/iterate.c

@@ -262,6 +262,7 @@ is_stairs(int block) {
         case 156: /* quartz stairs */
         case 163: /* acacia wood stairs */
         case 164: /* dark wood stairs */
+        case 180: /* red sandstone stairs */
             return 1;
     }
     return 0;