Added decorator use_field_name_or_array.
Added decorator use_field_name_or_array.

The decorator use_field_name_or_array wraps a function, whose first two
arguments are a grid followed by an array, and returns a function that
takes either a field name or an array of values.

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