A special presentation regarding mental health will be offered Sunday at Branson's Church of the Harvest.   Presented by Gail and Randy Baar with help from Dr. Paul Collins, the event, set for October 19, will give a biblical perspective on a topic that is often considered taboo amongst Christians.   The presentation, "Mental Health Unchained," will offer an in-depth look at a challenge faced by many in our country and our community and offer biblical principles to apply, as