ENH: Display only vessely image after enhancement
ENH: Set Slicer Dark Style as default

This should be changed once a Prometheus style is defined.
FIX: Clear paint brush on Segmentation step exit
ENH: Modify the slice views with the configuration name
ENH: Disable auto update of slices when adding new nodes
BUMP: Bump TubeTk to benefit from CLP fixes
ENH: Fix workflow module palette

As explained in [1], since the palette of the Slicer designer plugin base
class (see [2]) is explicitly set, the application wide palette is not
propagated. This commit workaround this issue by explicitly setting the
palette of the widget loaded from UI file.

To find out which widget have an explicit palette, the following
snipped can be used:

for w in slicer.app.allWidgets():
    if w.testAttribute(qt.Qt.WA_SetPalette):
        print("%s - [%s] (%s)" % (w, w.objectName, w.parent()))

[1] http://blog.qt.digia.com/blog/2008/11/16/font-and-palette-propagation-in-qt/
[2] https://github.com/Slicer/Slicer/blob/22f1c99f28d52f58070e31849d33a3a50e4501a6/Base/QTGUI/DesignerPlugins/qSlicerWidgetPlugin.cxx#L41
ENH: Rename ExtractSkeletonStep to ExtractSeedsStep
ENH: Complete/update the ExtractSeeds step
ENH: Customize json loading to support step parameters

To be able to have custom parameter files for steps, the json loading was
modified a little bit.
The file that have a .dict extension are treated has dictionnaries that
can be used when updating the configuration of modules.
Merge remote-tracking branch 'githubOrigin/workflow'

* githubOrigin/workflow: (25 commits)
  ENH: Customize json loading to support step parameters
  ENH: Complete/update the ExtractSeeds step
  ENH: Rename ExtractSkeletonStep to ExtractSeedsStep
  ENH: Fix workflow module palette
  BUMP: Bump TubeTk to benefit from CLP fixes
  ENH: Disable auto update of slices when adding new nodes
  ENH: Modify the slice views with the configuration name
  FIX: Clear paint brush on Segmentation step exit
  ENH: Set Slicer Dark Style as default
  ENH: Display only vessely image after enhancement
  ENH: Refactor vessel enahncement step to use the correct cli
  ENH: Add comboboxes for additionnal input parameters to the PDF segmenter
  ENH: Remove unecessary Register widget parameters
  ENH: Create an adaptive layout
  ENH: Improve segmentation Step to allow an easier editing interface
  ENH: Resample step before Register step
  ENH: Collapse the data probe automatically
  ENH: Update Resample Step to handle 1 to 3 inputs
  ENH: Improve icons
  ENH: Make registration type available in intermediate workflow
  ...