Fixes Issue #5: Function sha3 has been deprecated in favor of keccak256
Fixes Issue #5: Function sha3 has been deprecated in favor of keccak256

Signed-off-by: Nikita <5c9993fe5c1b9bfc216420fea06629aef1fdc9c2@gmail.com>

Leondra/PXLT,nikita-fuchs/PLToken