PORT ST. LUCIE — GL Homes waited 12 years to start building homes on a six-square mile agricultural tract known as Riverland because of the precipitous drop in the city's property values during the Great Recession. It looks like it will be worth the wait because GL Homes plans to develop several communities for people age 55-and-up and the housing market for retiring baby boomers is taking off in western Port St. Lucie. Valencia Cay, a 55-plus community, sold 249 homes since