Remove py2to3 from tomviz python modules
Remove py2to3 from tomviz python modules

This file was removed from the source code, but it was not removed
from the CMakeLists.txt file. It appears to be causing a build
error in Windows. Remove it to see if this fixes it.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz