move "single_copy_species" back from being its own element (yay) to being an attribute in the root (boo)
move "single_copy_species" back from being its own element (yay) to
being an attribute in the root (boo)

Change-Id: I7fad5482b6bb9986742fa67d6c65aa1cc581091c

benedictpaten/cactus,benedictpaten/cactus,benedictpaten/cactus,benedictpaten/cactus,benedictpaten/cactus