python -- assign lookup tables by name

Added a reader for ParaView's exported XML colormaps to simple.py.
With the reader one could load and assign loookup tables to arrays
by lookup table name. ParaView's default LUT's (in ColorMaps.xml)
are installed and loaded by default in the reader's constructor.

Change-Id: Idd35965518f38f89c2d71be03e5baf7f501e99d6
Merge topic 'simple-py-lookup-tables' into next

9c4f469 python -- assign lookup tables by name