Add some normalmaps with heightmap in alpha channel

mods/default/textures/default_brick_normal.png

mods/default/textures/default_cobble_normal.png

mods/default/textures/default_desert_sand_normal.png

mods/default/textures/default_desert_stone_normal.png

mods/default/textures/default_mineral_coal_normal.png

mods/default/textures/default_mineral_copper_normal.png

mods/default/textures/default_mineral_diamond_normal.png

mods/default/textures/default_mineral_gold_normal.png

mods/default/textures/default_mineral_iron_normal.png

mods/default/textures/default_mineral_mese_normal.png

mods/default/textures/default_sand_normal.png

mods/default/textures/default_sandstone_brick_normal.png

mods/default/textures/default_stone_brick_normal.png

mods/default/textures/default_stone_normal.png