Incorrect digest algorithm names

[pwinckles]

The spec states:

The name of the checksum algorithm MUST be normalized for use in the manifest's filename by lowercasing the common name of the algorithm and removing all non-alphanumeric characters.

However, this implementation includes the following incorrect (by the specs, definition) algorithm names:

shake_128
shake_256
sha3_512
sha3_224
sha3_256
sha3_384