"isolov submitted rdb with tag master for tdaq-99-00-00"

=== rdb ===

follow IDL and common_utils changes (Igor Soloviev) add rdb::string_dup to be used across whole package instead of CORBA::string_dup (Igor Soloviev)

1. refactor inform() and push_db_changes() changes in IDL removing unsed parameters; 2. add prefetch_schema (Igor Soloviev) add test for RDB replication (Igor Soloviev)