update readme and add perf test results
update readme and add perf test results

mourner/rbush,korczis/rbush,opentable/rbush,MazeMap/rbush,opentable/rbush,landonb/rbush,landonb/rbush,korczis/rbush,josl/rbush,josl/rbush,mourner/rbush,MazeMap/rbush