Match point with a five point lead wasn't enough Wednesday at the Barton Gym as the Barton Community College volleyball team's grasp of victory was snatched away by an improbable Colby Community College comeback.   The Cougars took the first and third set 25-22 and 26-24, with Colby answering the call taking the second and fourth 25-18 and 25-22 forcing a decisive fifth where the Trojans rallied from a five-point 14-9 deficit scoring seven straight points to win 16-14.   Barton slips to 2-3 in conference play dropping their eighth straight match falling to 5-11 while Colby's third straight win improves the Trojans to 3-2 and 6-7 overall.  The road to recovery for the Cougars begins Saturday in Concordia as Barton takes on Cloud County Community College in a 2:00 p.m. first serve at Bryant Gymnasium.