lastidnotfound step 2: (#1300)

lastidnotfound step 2:
  * move "record stage", aka poh_service into banking stage
  * remove Entry.has_more, is incompatible with leader rotation
  * rewrite entry_next_hash in terms of Poh
  * simplify and unify transaction hashing (no embedded nulls)
  * register_last_entry from banking stage, fixes #1171 (w00t!)
  * new PoH doesn't generate empty ledger entries, so some fixes necessary in 
         multinode tests that rely on that (e.g. giving validators airdrops)
  * make window repair less patient, if we've been waiting for an answer, 
          don't be shy about most recent blobs
   * delete recorder and record stage
   * make more verbost  thin_client error reporting
   * more tracing in window (sigh)

src/thin_client.rs

@@ -192,7 +192,7 @@ impl ThinClient {
         self.balances
             .get(pubkey)
             .map(Bank::read_balance)
-            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "nokey"))
+            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "AccountNotFound"))
     }
 
     /// Request the finality from the leader node
@@ -670,7 +670,9 @@ mod tests {
         let balance = client.poll_get_balance(&bob_keypair.pubkey());
         assert!(balance.is_err());
 
-        server.close().unwrap();
+        server
+            .close()
+            .unwrap_or_else(|e| panic!("close() failed! {:?}", e));
         remove_dir_all(ledger_path).unwrap();
     }
 }