ENH: New color rescale based on visible data

Change-Id: Idbf484757c565729656bb8dc8fd87b8359fb38e3
Make vtkExtractSelectionRange work in parallel.

Also cleaned up code: using macros when applicable and removing
unnecessary overloads.

Change-Id: I2b7941f822a3d00f92348ff3f7eef0f93ccb747b
Update icon for reset-to-visible-range.

Change-Id: I14e71b960e98f800e6eb08f153701e6b9399ebd1
Minor code restructuring for consistency.

Moving the method to rescalate LUT to visible range to
vtkSMPVRepresentationProxy from vtkSMTransferFunctionProxy.

Moving ExtractSelectionRange to "internal_filters".

Change-Id: I6a734d20b146497ba74e59e8875ec3db19316b77
Adding test to test resetting to visible range.

Change-Id: Ib4ec7037fe8d894805db33c0dddaeb3a69956d7e
Fix visible range warnings and test

Change-Id: I526e7b98e0631b041e0063c9e31cb491e24f963b
Update baselines.

Change-Id: Id739ed2a45927ec507772a81903783984366977b
Merge topic 'visible_range' into next

3edc5e0f Update baselines.
4ae5a955 Fix visible range warnings and test
30ec5eb0 Adding test to test resetting to visible range.
c161dd14 Minor code restructuring for consistency.
52367802 Update icon for reset-to-visible-range.
90269fc4 Make vtkExtractSelectionRange work in parallel.
5d36f761 ENH: New color rescale based on visible data