Enable the transfer function charts by default

New API for the transfer function charst has been backported into VTK.

CMakeExternals/VTK.cmake

@@ -31,7 +31,7 @@ IF(${add_project} OR CTK_LIB_Scripting/Python/Core_PYTHONQT_USE_VTK)
 
   IF(NOT DEFINED VTK_DIR)
 
-    SET(revision_tag 0e6c2a52501efab53e1c4d74910bcb1155245e1b)
+    SET(revision_tag 4b419e67427e974b51ea0812bae25b174426a2ff)
     IF(${proj}_REVISION_TAG)
       SET(revision_tag ${${proj}_REVISION_TAG})
     ENDIF()

Libs/Visualization/VTK/Widgets/ctk_library_options.cmake

@@ -6,5 +6,5 @@
 #
 
 SET(ctk_library_options
-  USE_TRANSFER_FUNCTION_CHARTS:OFF
+  USE_TRANSFER_FUNCTION_CHARTS:ON
   )