PHOTOS (4, one color on cover) CHARTS (2); (File photo/LOU TOMAN)Eastern Airlines' departure from operation is one of the more recent signs of decline in Miami. While other Florida cities are attracting business from out of state, Miami's corporate community is shrinking. (Staff photos/NICHOLAS R. VON STADEN)CenTrust Bank, which was seized last year, had employed about 2,500 in Dade County, including at CenTrust Tower in downtown Miami. MIAMI'S STRUGGLE: Troubles with companies based in Miami, such as failed AmeriFirst, shrink the corporate community.(COLOR) (Cover) Terremark building was built as headquarters for General Development Corp. But it now uses only part of the 130,000 square feet it first leased.