Moved calculation of current layer repr into StaticHistogramModel.
Final changes on refactor allowing static search and histograms.
Draw static histogram when showing it.  Fetch histogram on view create.
Merge branch 'master' into refactor-static-histogram-model-and-widget
Cause composite view to fetch histogram on initialization.
Merge branch 'master' into refactor-static-histogram-model-and-widget
Merge pull request #119 from Kitware/refactor-static-histogram-model-and-widget

Refactor static histogram model and widget