Write an implementation for IDataOutput

[dktapps]

This can then be used to reproduce all format variations of NBT as needed. This would be beneficial particularly for block palette extraction, since the use of non-standard varint NBT has caused confusion in the community.

Reimplementing IDataOutput would be simpler than trying to assemble a header for any of the existing implementations within MCPE itself, since they wouldn't randomly change because of MCPE changes, or break because of a symbol name change.