add blank material files

valve/pbr/halflife.wad/+BUTTON4/+BUTTON4.mat

@@ -0,0 +1,16 @@
+
+{
+"for" "+0BUTTON4"
+//"basecolor_map" "+0BUTTON4.png"
+//"normal_map" "+0BUTTON4_normal.png"
+//"metal_map" "+0BUTTON4_metal.png"
+//"roughness_map" "+0BUTTON4_roughness.png"
+}
+
+{
+"for" "+ABUTTON4"
+//"basecolor_map" "+ABUTTON4.png"
+//"normal_map" "+ABUTTON4_normal.png"
+//"metal_map" "+ABUTTON4_metal.png"
+//"roughness_map" "+ABUTTON4_roughness.png"
+}