textures: add dedicated non-animated MC series.

Nothing else in FD's repetoire quite matches the deep, rich, earthy green-brown that these textures have. They're perfect for certain outdoor environments - except in Final Doom they're part of this really unnatural fade-in fade-out animation. This doesn't really matter in FD in isolation but if you try to load a Final Doom-compatible animation definition then the entire intended effect is ruined.

This commit also updates E1M1 to use these new textures.

lumps/textures/textures.cfg

@@ -3831,6 +3831,28 @@ LITEBLU5        32      128 ; Variant of LITE3 but blue.
 *   BLITC0      24      112
 *   BLITC0      24      120
 
+; Non-animated versions of the MC textures,
+; in case we get the MC animations working in FD
+; (or a level gets exported as a Final Doom PWAD).
+MCSTAT1        128     128
+*   MC12      0       0
+MCSTAT2        128     128
+*   MC13      0       0
+MCSTAT3        128     128
+*   MC14      0       0
+MCSTAT4        128     128
+*   MC15      0       0
+MCSTAT5        128     128
+*   MC16      0       0
+MCSTAT6        128     128
+*   MC17      0       0
+MCSTAT7        128     128
+*   MC18      0       0
+MCSTAT8        128     128
+*   MC19      0       0
+MCSTAT9        128     128
+*   MC20      0       0
+
 ; These textures are only in FreeDM
 
 #ifdef FREEDM