Removed deprecated and unused is_point_on_grid.
Removed deprecated and unused is_point_on_grid.

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