STYLE: update some examples for mesa-18.3.4

- still needs more testing to determine the best combination of versions

makeMesa.example

+#!/bin/sh
+# An example for building mesa with llvm
+
+mesa=mesa-18.3.4
+llvm=llvm-4.0.1
+
+set -x
+./makeMesa \
+    $mesa $llvm
+    "$@"
+
+#------------------------------------------------------------------------------

makeParaView.example

@@ -9,11 +9,12 @@
 
 # mesa=mesa-11.2.2
 # mesa=mesa-13.0.3
-mesa=mesa-17.1.1
+# mesa=mesa-17.1.1
+mesa=mesa-18.3.4
 
 set -x
 ./makeParaView \
-    -mpi=0 \
+    -mpi \
     -mesa-prefix $WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$mesa \
     -python \
     -suffix mesa-mpi-py \

makeVTK.example

@@ -2,10 +2,11 @@
 # An example for building particular combinations of VTK with
 # - mesa (off-screen only)
 
-vtk=VTK-9.0.0
+vtk=VTK-8.2.0
 # mesa=mesa-11.2.2
 # mesa=mesa-13.0.3
-mesa=mesa-17.1.1
+# mesa=mesa-17.1.1
+mesa=mesa-18.3.4
 
 # Module_vtkAcceleratorsVTKm    : Request building vtkAcceleratorsVTKm
 #
@@ -19,5 +20,4 @@ set -x
     $vtk "$@" \
     Module_vtkAcceleratorsVTKm=ON
 
-
 #------------------------------------------------------------------------------