tutorials: Consistency of All* scripts

Various minor changes to tutorial scripts. In particular, ensuring that
they all change to the containing directory so that batches of tutorials
can be run easily from the root of the installation.

tutorials/multiphaseEuler/pipeBend/Allclean

@@ -1,7 +1,7 @@
 #!/bin/sh
 cd ${0%/*} || exit 1    # Run from this directory
 
-# Source clean functions
+# Source tutorial clean functions
 . $WM_PROJECT_DIR/bin/tools/CleanFunctions
 
 cleanCase && rm -f *.eps

tutorials/multiphaseEuler/pipeBend/Allrun

@@ -1,7 +1,7 @@
 #!/bin/sh
 cd ${0%/*} || exit 1    # Run from this directory
 
-# Source run functions
+# Source tutorial run functions
 . $WM_PROJECT_DIR/bin/tools/RunFunctions
 
 # Mesh

tutorials/multiphaseEuler/pipeBend/validation/createGraphs

@@ -2,7 +2,7 @@
 
 if ! which gnuplot > /dev/null 2>&1
 then
-    echo 'gnuplot not found - skipping graph creation' >&2
+    echo "gnuplot not found - skipping graph creation" >&2
     exit 1
 fi