Improved tests and support for ResultSet CallableStatement and SavePoint.

ResultSet implementation to fall back to proxy only mode when features like first and last are used to modify the position of the ResultSet.
Improved error handling for callProxy operations.

Author: rrobetti

ojp-grpc-commons/src/main/proto/StatementService.proto

@@ -158,6 +158,7 @@ enum CallType {
     CALL_EXECUTE = 43;
     CALL_ADD = 44;
     CALL_ENQUOTE = 45;
+    CALL_REGISTER = 46;
 }
 
 message TargetCall {