Add the cliargs and entrypoint for the CLI client
Update all tests
Import chunkerror
Refactor load_uri to from_uri and raise errors
Refactor from_json
Make uri a property
If there are no hashes, raise an exception instead
Make has_hashes a prop
Remove unused meths that were essentailly props anyway (unused)
Reorg exceptions alphabetically
Use the damn chunkerror
Fix return to return instance of chunk given removal of self as  areturn on 'from_json' call
Rename checkpath to upload_check_path, and write download method
Remove _download_chunk