The Connecticut Office of Historic Preservation has responded to Newtown's plans to redevelop two empty buildings on the Fairfield Hills campus saying they'll support the project, as long as  Newtown keeps all the other vacant former hospital buildings for at least five years after the completion of the redevelopment.  The Newstimes reports that the town was seeking the state's backing as it seeks historic preservation tax credits from the National Park Service.  Boston-based WinnDevelopment is looking to convert Kent House and Shelton House, built in 1940 and 1933 respectively, into housing and shops.  Newtown has demolished other unsafe structures and officials have previously said the remaining buildings are dilapidated and need to be demolished as well.  First Selectman Dan Rosenthal suggested a joint meeting of the Board of Selectmen, Board of Finance and Legislative Council about how to proceed.