Added ability to share/detach LUTs.

Modules can now detach their LUTs from the DatSource's LUTs.
Update dax Modules to use new lut setup.

ModuleStreamingContour doesn't say it needs luts still since it doesn't
pass scalars. We can fix that when it starts passing scalars.
Update ModuleSlice to use LUTs from Module/DataSource.
Add serialization support for the new color map stuff.

Color maps are now serialized (both the data source color maps, and the
module color maps).
Merge branch 'lut_fixes'

Add ability to detach color map for each module. By default, a module
uses the data-source's color map but one can detach it and then setup
separate color map for each module.

This also added code to serialize/deserialize these color maps in state
files.

* lut_fixes:
  Add serialization support for the new color map stuff.
  Update ModuleSlice to use LUTs from Module/DataSource.
  Update dax Modules to use new lut setup.
  Added ability to share/detach LUTs.