An Aliquippa pastor is marking a special milestone this weekend. 78-year-old Bishop Melvin E. Clark — and Aliquippa’s Church in the Round, the ministry he built in the city’s Plan 11 Extension neighborhood — will celebrate Clark’s 50 years as a church and community leader with services at the church this weekend. The celebration will be capped with a banquet in his honor on Monday. Beaver County Radio News Correspondent Sandy Giordano has the story…