Change Nether_brick_item in Nether brick factory

Change Nether_brick_item in Nether brick factory into Nether_brick and then I div by 4 the output.

Nether_brick_item is the item and Nether_brick is the block.

After making 150 stacks of blocks I feel the pain.
Merge pull request #19 from ribagi/patch-35

Change Nether_brick_item in Nether brick factory