Removed deprecated node_index_at_active_cells.
Removed deprecated node_index_at_active_cells.

ManuSchmi88/landlab,landlab/landlab,landlab/landlab,Carralex/landlab,laijingtao/landlab,laijingtao/landlab,cmshobe/landlab,Carralex/landlab,cmshobe/landlab,amandersillinois/landlab,cmshobe/landlab,csherwood-usgs/landlab,RondaStrauch/landlab,RondaStrauch/landlab,landlab/landlab,csherwood-usgs/landlab,SiccarPoint/landlab,Carralex/landlab,ManuSchmi88/landlab,RondaStrauch/landlab,amandersillinois/landlab,ManuSchmi88/landlab,SiccarPoint/landlab