Hide previous layout when reverting to default
Hide previous layout when reverting to default

When the girder layout is something other than default, and navigateTo
is then called without any layout specified, the layout will revert
to the default layout, and the previous layout should be hidden.

msmolens/girder,essamjoubori/girder,opadron/girder,data-exp-lab/girder,kotfic/girder,chrismattmann/girder,manthey/girder,essamjoubori/girder,manthey/girder,Xarthisius/girder,opadron/girder,data-exp-lab/girder,girder/girder,jbeezley/girder,opadron/girder,sutartmelson/girder,data-exp-lab/girder,sutartmelson/girder,data-exp-lab/girder,Kitware/girder,adsorensen/girder,salamb/girder,msmolens/girder,jbeezley/girder,Xarthisius/girder,Xarthisius/girder,manthey/girder,kotfic/girder,manthey/girder,essamjoubori/girder,salamb/girder,RafaelPalomar/girder,adsorensen/girder,data-exp-lab/girder,RafaelPalomar/girder,jbeezley/girder,sutartmelson/girder,girder/girder,essamjoubori/girder,kotfic/girder,girder/girder,chrismattmann/girder,chrismattmann/girder,salamb/girder,msmolens/girder,Kitware/girder,Xarthisius/girder,Kitware/girder,sutartmelson/girder,chrismattmann/girder,msmolens/girder,RafaelPalomar/girder,adsorensen/girder,RafaelPalomar/girder,opadron/girder,RafaelPalomar/girder,sutartmelson/girder,opadron/girder,essamjoubori/girder,chrismattmann/girder,salamb/girder,kotfic/girder,girder/girder,adsorensen/girder,adsorensen/girder,Kitware/girder,kotfic/girder,jbeezley/girder,msmolens/girder,Xarthisius/girder,salamb/girder