Added constants for paths to example netcdf files.
Added constants for paths to example netcdf files.

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