Well, they finally went and did it. The CW canceled Supernatural. It is truly the end of an era. But fans of the series will get one more season before saying goodbye to the boys forever. After fifteen years on the air, Supernatural will end on The CW after Season 15, which series star Jensen Ackles promises "will be the big, grand finale of an institution" in a farewell video. Ackles, Jared Padalecki, and Misha Collins came together to announce the news in an emotional video on social media today. “We just told the crew that though we’re very, …