disable color clamping during read in case we ever read back something out of the 0..1 range
disable color clamping during read in case we ever read back something out of the 0..1 range

git-svn-id: 83c4c97093aeea62ac982fbfd516bf9db27f5c99@2233 c36c8488-0289-0348-9b64-b301f74bd9a7

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok