Rename vault.data.io to vault.data.format ns.
Rearrange some stuff.
Check in some more thoughts around vault.blob.filter.
Update blob docs with new direction.
Update the BlobStore and BlobCodec protocols.
Implement vault.blob.filter functions.
Moved code around, fixed errors.
Fix some blob tests.
Move BlobRef to vault.blob.digest.HashID.

Still shifting a lot of namespaces around.
Move some stuff between vault.blob.core and store.
Remove lots of codec-related code.
Start working on blob tests.
Fix store tests.
Move *digest-algorithm* to vault.blob.core.
Update file and memory blob stores.
Update some blob storage docs.
Change project's default namespace.
Merge branch 'blob-refactoring' into develop

Conflicts:
	project.clj
Fix typo in project.clj.
Rename vault.tool to vault.tool.main.