Temporarily include a map 0.

Eventually, we should read MAPINFO/UMAPINFO for this info.

doomcc/concat.py

@@ -48,8 +48,9 @@ class Concat(doomcc.doom_base.Wad):
         # Presumably fixable, but it's easier to just make one graph per video
         # and mux everything together at the end.
         # TODO: Support UDoom in literally any way.
+        # TODO: Read UMAPINFO if it's available.
         d2maps = (
-            [str(x).zfill(2) for x in range(1, 16)]
+            [str(x).zfill(2) for x in range(0, 16)]
             + ["31", "32"]
             + [str(x) for x in range(16, 31)]
         )