ENH: Add threshold sliders to control scalar opacity

svn-url: http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=18375
git-svn-id: http://svn.slicer.org/Slicer4/trunk@18375 3bd1e089-480b-0410-8dfb-8563597acbee

SuperBuild/External_CTK.cmake

@@ -35,7 +35,7 @@ if(NOT DEFINED CTK_DIR)
 
   ExternalProject_Add(${proj}
     GIT_REPOSITORY "${git_protocol}://github.com/commontk/CTK.git"
-    GIT_TAG "00b225b8250d0dcf622a8da2076f93d1bbb01b2c"
+    GIT_TAG "e6edd5b7a40ee1c5125122b9a9056bdcf00016c2"
     SOURCE_DIR ${CMAKE_BINARY_DIR}/${proj}
     BINARY_DIR ${proj}-build
     CMAKE_GENERATOR ${gen}