STY: Change ITK_OVERRIDE for override in whole code (find Modules -type f -exec sed -i 's/ITK_OVERRIDE/override/g' {} +)

BUG: Fixing bug #1467. No Update() should happen on filters whatsoever, unless you know for sure that the Udpate() call will not load whole image in memory. No local pointers to filters are allowed (because the streaming pipeline disappears at the end of the method)