* Add non-fungible token program
* Remove issuer and id from state
* Boot NftInstruction and NftState
* Rename NFT to Ownable
Maybe this should be "Owned" to avoid confusion with an Ownable trait?
* Rename directory
* Delete unreachable branch
* Don't use copy_from_slice - need an error, not a panic.
* Rename contract_pubkey to account_pubkey