WILMINGTON, Del. — The crowd of lawmakers, librarians, parents, and a few young children were enthralled as Dolly Parton’s angelic voice filled the room at the Wilmington Public Library. On stage, just feet away, Parton — clad in a multicolor vest and strumming a multicolor guitar — sang her 1971 hit “Coat of Many Colors.” Thursday’s lunchtime serenade was part of an event for the country music icon’s Imagination Library, a book gifting program for young children. The 76-year-old singer travels the country promoting the initiative, one of her many philanthropic endeavors. The Delaware visit ca…