WATERVILLE — Looking back over the four decades he has owned the Bob-In restaurant and lounge on Temple Street, Gubby Karter says he has been a good citizen in the Waterville community. But he says the bar itself developed a reputation it never deserved. Karter, who turned 70 last week, has agreed to sell the venerable tavern at the corner of Front Street to his brother Fred, owner of Jokas’ Discount Beverage next door.