Added pybind11 wrapping for DataSource
Added pybind11 wrapping for DataSource

It currently only uses two functions: darkData and whiteData.

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

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