* Added some simple unit tests for imshow_grid.
* Added some simple unit tests for imshow_grid.



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