Add library ruins

- Adds two variants of library ruins: surface (generates in forested biomes) and underground (generates everywhere)
- Adds loot table support to bookshelves
- Adds antique atlas markers for library ruins
- Adds bookshelves and lecterns to the wood type template processor
- Makes bookshelves and lecterns rotate correctly in structure templates
- Generalises most of the methods in WorldGenSurfaceStructure to a new superclass WorldGenWizardryStructure

src/main/java/electroblob/wizardry/block/BlockBookshelf.java

@@ -84,6 +84,18 @@ public class BlockBookshelf extends BlockHorizontal implements ITileEntityProvid
 		return this.getDefaultState().withProperty(FACING, placer.getHorizontalFacing().getOpposite());
 	}
 
+	// Why on earth are these two not in BlockHorizontal?
+
+	@Override
+	public IBlockState withRotation(IBlockState state, Rotation rotation){
+		return state.withProperty(FACING, rotation.rotate(state.getValue(FACING)));
+	}
+
+	@Override
+	public IBlockState withMirror(IBlockState state, Mirror mirror){
+		return state.withRotation(mirror.toRotation(state.getValue(FACING)));
+	}
+
 	@Override
 	public void onBlockAdded(World worldIn, BlockPos pos, IBlockState state){
 		super.onBlockAdded(worldIn, pos, state);

src/main/java/electroblob/wizardry/block/BlockLectern.java

@@ -18,6 +18,8 @@ import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.EnumFacing;
 import net.minecraft.util.EnumHand;
+import net.minecraft.util.Mirror;
+import net.minecraft.util.Rotation;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.IBlockAccess;
 import net.minecraft.world.World;
@@ -103,6 +105,16 @@ public class BlockLectern extends BlockHorizontal implements ITileEntityProvider
 		return this.getDefaultState().withProperty(FACING, placer.getHorizontalFacing().getOpposite());
 	}
 
+	@Override
+	public IBlockState withRotation(IBlockState state, Rotation rotation){
+		return state.withProperty(FACING, rotation.rotate(state.getValue(FACING)));
+	}
+
+	@Override
+	public IBlockState withMirror(IBlockState state, Mirror mirror){
+		return state.withRotation(mirror.toRotation(state.getValue(FACING)));
+	}
+
 	@Nullable
 	@Override
 	public TileEntity createNewTileEntity(World world, int meta){