Added from_path classmethod to init from file.
Added from_path classmethod to init from file.

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