CEE MARKETS-Warsaw leads stocks rise, Hungarian bonds firm ahead of auction

* Fed comments on rate caution helps CEE assets * Warsaw leads stock gains, JSW and PGNiG Q1 results help * Hungarian bond auction seen drawing strong demand By Sandor Peto BUDAPEST, May 25 (Reuters) - Warsaw led Central European equities higher on Thursday as emerging market stocks firmed after the U.S. Federal Reserve signalled cautious approach to rate hikes and Polish energy firms PGNiG and JSW reported strong earnings. The prospect of slower U.S. rate hikes than had