Added netCDF4 to requirements.
Added netCDF4 to requirements.

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