Write first round of unit tests

[phrohdoh]

Status	System under test	Relevant commit(s)
done	Kind::try_from_bytes	1b802c83a5bfad880db69e5c1794ae1a02470f08
done	Archive::from_bytes	dd7f7e13d67728231ba791200700b3ef319ba6d8, 83bfbde75ac9de62d7ead86339a094fb3b7bca22, 93fef5f2ca1439f655af29c58791a2b29a78a4c0
done	Archive::read_kind	83bfbde75ac9de62d7ead86339a094fb3b7bca22
done	Archive::read_size	bcbaa696563c9db811c2ec2c7b444b5a32e53388
done	Archive::read_entry_metadata_table	19eaf98a8ef06fff537f038f485105823c66bba2
done	Archive::get_bytes_via_table	b2733ecb7964a1dbed98cc07288bd84bde298fca

[phrohdoh]

There is of course always more tests that can be written but for the time being I'm going to close this as the above functions have been tested.