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