* Add collabsible sidebar for HTML documentation.
* Add collabsible sidebar for HTML documentation.

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