Update PV tests to use ExternalData

Change-Id: If6a379edf92c459ee35bab1914da078191f31f57
Fix PARAVIEW_DATA_ROOT

Change-Id: I8432a060bed14c8630ef9610fb99894a5d6fa7de
Fix data paths in Application tests

Change-Id: Icb6f5328c05e890a89d35d6bde2deae6031057b9
PARAVIEW_DATA_ROOT is now always available

Change-Id: Iac1d5afb7d990d4fea68f29cc1ebb9b30e230d6c
Add dependencies for non-default data targets

Change-Id: I54fd5be9ec211c36bcd295ed55bad9b4380b95c9
Download data from paraview.org as well

This is where Gerrit-uploaded data files will reside.

Change-Id: If2451c16bfcfbd4ece887de2e59780233822fe41
Prevent a duplicate data target rule

Change-Id: I11683439d8c1e7f10612111b5b39fc268f5fdab0
Update VTK

Change-Id: I6be864460b818be5b71764fc4fc971be4518d26f