STYLE: clean out clutter in paraview config files (issue #176)

Now reduced to 3 environment variables:
    ParaView_DIR         - paraview installation directory
    ParaView_INCLUDE_DIR - paraview include directory
    PV_PLUGIN_PATH       - paraview plugin directory for OpenFOAM modules

Previously also had (ParaView_MAJOR, ParaView_VERSION).

ThirdParty makeParaView adjusted accordingly.

ENH: improved configuration possibility for non-ThirdParty paraview
installation.

BUG: csh foamPV alias was completely incorrect.