Add get_signature_status() to SyncClient

And move bank::Result to transaction module.

sdk/src/transaction.rs

@@ -7,6 +7,7 @@ use crate::pubkey::Pubkey;
 use crate::short_vec;
 use crate::signature::{KeypairUtil, Signature};
 use bincode::serialize;
+use std::result;
 
 /// Reasons a transaction might be rejected.
 #[derive(Debug, PartialEq, Eq, Clone)]
@@ -46,6 +47,8 @@ pub enum TransactionError {
     InvalidAccountIndex,
 }
 
+pub type Result<T> = result::Result<T, TransactionError>;
+
 /// An atomic transaction
 #[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize)]
 pub struct Transaction {