use equal_range instead of seperate calls to lower_bound and upper_bound
use equal_range instead of seperate calls to lower_bound and upper_bound

thomaskrause/graphANNIS,thomaskrause/graphANNIS,thomaskrause/graphANNIS,thomaskrause/graphANNIS,thomaskrause/graphANNIS,thomaskrause/graphANNIS,thomaskrause/graphANNIS