Rewrite of the pipeline control widget

The pipeline control widget now stores its state in the
layer model, where most of the complicated logic has been moved.
The layer model stores additional information internally to
cache things like color and visibility.

One change from previous behavior is that (by default) all layers
will be hidden.  The default behavior can be changed by providing
a query string as the first argument to the constructor.
fixing initialization of layer model in various places
Fixed the way in which we add tools to be self contained in the views. This also fixed the tools connections when moving back and forth between exploration an dsearch.
fix incorrect merge conflict resolution

I picked the wrong direction in 7f33fed4 and reintroduced removed
code.
Merge pull request #73 from Kitware/fix-merge-conflict

fix incorrect merge conflict resolution
Revert "Merge branch 'colormap-chosen-field'"

This reverts commit 7f33fed440a4f68fe6b16de08ee01a5935addfbf, reversing
changes made to 630a52f7dbeff144b4cd22e84652dac8885131c7.
Revert "Merge pull request #73 from Kitware/fix-merge-conflict"

This reverts commit 497a2616d98511a3065e8278765ed0ef2463b2b0, reversing
changes made to 7f33fed440a4f68fe6b16de08ee01a5935addfbf.
Merge branch 'chart-view' into self-contained-tools

* chart-view:
  Fixed the way in which we add tools to be self contained in the views. This also fixed the tools connections when moving back and forth between exploration an dsearch.
Merge pull request #76 from Kitware/self-contained-tools

Self contained tools
fixed padding in preset LUT select of rendering toolbar.
Merge pull request #77 from Kitware/fix-rendering-select-padding

fixed padding in preset LUT select of rendering toolbar.
Merge branch 'pipeline-control-cleanup-old' into pipeline-control-cleanup

* pipeline-control-cleanup-old:
  fixing initialization of layer model in various places
  Rewrite of the pipeline control widget

Conflicts:
	web/src/js/app/views/Composite.js
	web/src/js/lib/widgets/PipelineWidget.js
fixed layer model initialization, and construction in the composite views.
hide the histogram tool initially for the composite view, remove debugging print.
Merge pull request #78 from Kitware/update-pipelinewidget-layermodel

Update pipelinewidget layermodel
Workbench infrastructure

For workbench dataset types, we now allow selection from the runs
and from their underlying analyses.
Remove unused code
Workbench element loading behavior