Fix test ns references.
Add type hints to eliminate reflection warnings.
Factor directory iteration into 'for-files' macro.
Factor some methods for blob stores and files.
Merge branch 'file-store-improvements'
Add memory-backed blob store.
Minor refactoring in ns vault.store.
Minor reformatting in vault.store.file.
Move prefix logic into vault.tool.blob.

The functions don't need to be in the general vault.store ns.
Add tests for ns vault.store.
Add tests for vault.data ns.

Fixed bug when base64-encoding byte arrays.