fix missing materials found with test chatcommand

src/commands.lua

@@ -18,5 +18,7 @@ minetest.register_chatcommand("xcompat_test_materials", {
                 end
             end
         end
+
+        minetest.chat_send_player(name, "Materials test complete")
     end
 })

src/materials/farlands_reloaded.lua

@@ -41,7 +41,8 @@ local materials = {
     silver_ingot = "fl_ores:iron_ingot",
     silicon = "mesecons_materials:silicon",
     string = "fl_plantlife:oxeye_daisy",
-    paper = "basic_materials:plastic_sheet",
+    paper = "",
+    book = "",
     iron_lump = "fl_ores:iron_ore",
     wool_grey = "",
     wool_green = "",
@@ -61,6 +62,7 @@ local materials = {
     chest = "fl_storage:wood_chest",
     cobble = "fl_stone:stone_rubble",
     brick = "",
+    obsidian_glass = "",
     water_source = "fl_liquids:water_source",
     water_flowing = "fl_liquids:water_flowing",
     dirt = "fl_stone:dirt",
@@ -75,4 +77,8 @@ local materials = {
     bowl = "",
 }
 
+if minetest.get_modpath("basic_materials") then
+    materials.paper = "basic_materials:plastic_sheet"
+end
+
 return materials

src/materials/mineclonia.lua

@@ -63,6 +63,7 @@ local materials = {
     chest = "mcl_chests:chest",
     cobble = "mcl_core:cobble",
     brick = "mcl_core:brick",
+    obsidian_glass = "",
     water_source = "mcl_core:water_source",
     water_flowing = "mcl_core:water_flowing",
     dirt = "mcl_core:dirt",