Fix python wrapping of CosmoTools VTK extensions

This commit refactors the readers and filters in the
CosmoTools VTK extensions, namely the GenericIO reader
and the Halofinder, such that, MPI is not included in
the headers which was causing compilation failures when
python was enabled.

Change-Id: I9b71dc99a9283255afd3346de655d8373b74feab
Merge topic 'gio-query-rank-neighbors' into fix-cosmotools-python-wrapping

Conflicts:
	ParaViewCore/VTKExtensions/CosmoTools/vtkPGenericIOReader.cxx

Change-Id: I9450c154b9acc2e516152cfc81df55838596007c
Merge topic 'fix-cosmotools-python-wrapping' into next

fe8f0f5 Merge topic 'gio-query-rank-neighbors' into fix-cosmotools-python-wrapping
24785de Fix python wrapping of CosmoTools VTK extensions