Move last ids (#2187)

* Break out last_ids into its own module
* Boot SignatureNotFound from BankError
* No longer return BankError from LastIds methods
* No longer piggypack on BankError for a LastIds signature status
* Drop all dependencies on the bank
* SignatureStatus -> Status and LastIds -> StatusDeque
* Unstable tests, issue 2193

tests/programs.rs

@@ -2,8 +2,8 @@ use solana;
 use solana_native_loader;
 
 use solana::bank::Bank;
-
 use solana::mint::Mint;
+use solana::status_deque::Status;
 #[cfg(feature = "bpf_c")]
 use solana_sdk::bpf_loader;
 use solana_sdk::loader_transaction::LoaderTransaction;
@@ -41,7 +41,7 @@ fn check_tx_results(bank: &Bank, tx: &Transaction, result: Vec<solana::bank::Res
     assert_eq!(result[0], Ok(()));
     assert_eq!(
         bank.get_signature(&tx.last_id, &tx.signatures[0]),
-        Some(Ok(()))
+        Some(Status::Complete(Ok(())))
     );
 }