Implement RPC call z_listoperationids and update z_getoperationstatus to take a list parameter.

src/rpcclient.cpp

@@ -100,6 +100,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "getblocksubsidy", 0},
     { "z_sendmany", 1},
     { "z_sendmany", 2},
+    { "z_getoperationstatus", 0},
     { "z_importkey", 1 }
 };