No developer has managed to build anything atop the Massachusetts Turnpike in Boston since Copley Place was built in the early 1980s. A mega-development outside Kenmore Square has the potential to change that record, and open up long sweeps of the Pike for redevelopment. For its work in unlocking acres of previously un-developable real estate, the Fenway Center project has invited a typically brutal Boston reward -- it has an abutter throwing up roadblocks and nursing petty grievances in court.