Find ParaView components correctly.

When developers use find_package(ParaView COMPONENTS foo), ensure that the 'foo'
is handled the same way as its handled for VTK modules.

Change-Id: I124c2c3dc9c700f217ef07611eee7f83c4ce7daa
HACK: Fix Python initialization in vtkPVPythonCatalyst.

vtkPVPythonCatalyst module needs to init Python in static builds and hence needs
to depend on "all enabled modules". To do this cleanly, we decided to
add_subdirectory(...) for this module directly. That would work but there's 1
problem: VTKConfig.cmake builds up a VTK_MODULES_ENABLED variable that doesn't
end up including this vtkPVPythonCatalyst module. We have plans to fix VTK, but
until that happens, we process vtkPVPythonCatalyst as part of the module-top
loop (skipping the CMakeLists.txt) and then processing it again at a later time.

Change-Id: I1ad4465bb18423b3b06946db066ae6f1ee344132
Merge topic 'catalyst_2.0' into next

7f001ba HACK: Fix Python initialization in vtkPVPythonCatalyst.
efe7beb Find ParaView components correctly.