add FVOID, resource files for new DCAFE style textures for XE1M3 (and beyond!)

TEXTURES.txt

@@ -1,5 +1,5 @@
 // Texture definitions generated by SLADE3
-// on Sun Mar  3 15:51:15 2024
+// on Sat May 25 12:05:20 2024
 
 Texture "GRNOA0", 64, 45
 {
@@ -106,4 +106,9 @@ Texture "EMPL001", 128, 128
 	Patch "EMPL001", 0, 0
 }
 
+Texture "FVOID", 4, 4
+{
+	Patch "FVOID", 0, 0
+}
+
 // End of texture definitions