`EACL` method of `Container` contract returns binary session token, key and
signature along with eACL table.
Provide `Signature`, `PublicKey` and `SessionToken` getters from
`EACLValues` structure. Parse and set all values in `Client.EACL` methods.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`eACL` method of `Container` contract returns structure with 4 fields (the
4th is a recently added binary session token).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
