Support new Int_Array tag; change Byte_Array tag to use byte arrays

The first commit adds support for the new Int_Array tag introduced with Anvil. The payload is represented in Haskell as a UArray Int32 Int32 .

The second commit changes the Haskell payload representation of Byte_Array to be UArray Int32 Int8 . This latter representation seems better to me for several reasons: Minecraft bytes are supposed to be signed, indexing efficiency should be better, parallels Int_Array.

I am currently working on a Haskell round-tripping translator from Minecraft level files to XML. So far, the translator can properly decode region files in Anvil .mca format, but hasn't yet done anything with that. Thanks huge for Data.NBT, which is a big help on this project!