
Optimized map_index for the case where index_only is True and the index
is sorted.



tommy-u/chaco,tommy-u/chaco,burnpanck/chaco,burnpanck/chaco,tommy-u/chaco,ContinuumIO/chaco,ContinuumIO/chaco,ContinuumIO/chaco,burnpanck/chaco,ContinuumIO/chaco