VAN BUREN, Maine – Jason and Dayton Grandmaison, two brothers and Van Buren natives, are working hard to save one of the town’s most well-known historic establishments: the Gayety Theatre building. The iconic structure has been a part of Van Buren for over a century. It was built in 1920, and opened the following year on March 17. The theater entertained residents for over half a century, but eventually closed on Dec. 14, 1983. It was first owne…