chunks: add compute import
Merge branch 'bcolz-chunks' of github.com:mrocklin/blaze into bcolz-chunks

Conflicts:
	blaze/compute/chunks.py
into: bcolz/blz and types
Merge branch 'bcolz-chunks' of github.com:mrocklin/blaze into bcolz-chunks

Conflicts:
	blaze/bcolz.py