Dobama enters its second 50 years with a new theater and a new play...by Michael Gill...Everywhere you look at Dobama Theatre this week, you'll find the past and future pulling against each other. After more than four decades in a Coventry Road basement and four years without a home, the company begins its 50th season in a new facility on Lee Road, in the former YMCA building across the street from the Cleveland Heights/University Heights Public Library. Beneath the stage are the tile remains of the swimming pool. Upstairs in the offices, there's a new…