Residents will have to wait a bit longer for the reopening of the renovated Boyden Library building. A plan that has been in the works for well more than a decade is close, but not there yet, said library officials, who had hoped to open the doors on the $11.6 million project by the end of July. The grand opening date, however, is still a “moving target,” they said. Work on the 20,000-square-foot library and its 14,000-square-foot addition features upgrades such as a spacious upper-level children’s library, coined the Tree House by library staff and trustees. The town and the Massachusetts Board of Library Commissioners are funding most of the project, with the rest raised by donations.