Update the rest of the blast resistance values

The values have been updated according to this list:

https://minecraft.gamepedia.com/Module:Blast_resistance_values

mods/ITEMS/mcl_books/init.lua

@@ -342,7 +342,7 @@ minetest.register_node("mcl_books:bookshelf", {
 	groups = {handy=1,axey=1, flammable=3,building_block=1, material_wood=1},
 	drop = "mcl_books:book 3",
 	sounds = wood_sound,
-	_mcl_blast_resistance = 7.5,
+	_mcl_blast_resistance = 1.5,
 	_mcl_hardness = 1.5,
 })