SALISBURY — As needed, Dr. Norman Sloop tends to the Bradshaw gravesite at Chestnut Hill Cemetery. Not far from the mountainous monument to E.B.C. Hambley, the Bradshaw plot includes the markers for two of Sloop’s uncles, Carl and Sam Bradshaw, and a larger stone for his grandparents, Eula and D.C. Bradshaw. But it’s the life — and death — of William Carl Bradshaw, who everybody knew as Carl, that has always intrigued Sloop. He never knew this uncle, but back at his home off