tutorials: Renamed .org -> .orig

See http://www.openfoam.org/mantisbt/view.php?id=2076
  - .org is the file extension for emacs org-mode as well
  - .orig is more to the point (.org isn't always recognized as "original")
  - .original is too long, although more consistent with the convention
    of source code file naming

Update script contributed by Bruno Santos

tutorials/multiphase/interPhaseChangeFoam/cavitatingBullet/Allclean

@@ -7,7 +7,7 @@ cd ${0%/*} || exit 1    # Run from this directory
 # Remove surface
 \rm -f constant/triSurface/bullet.stl.gz
 
-# Remove copy of 0.org
+# Remove copy of 0.orig
 rm -rf 0
 
 cleanCase

tutorials/multiphase/interPhaseChangeFoam/cavitatingBullet/Allrun

@@ -13,7 +13,7 @@ runApplication blockMesh
 # Generate the snappy mesh
 runApplication snappyHexMesh -overwrite
 
-cp -r 0.org 0
+cp -r 0.orig 0
 
 # Initialise with potentialFoam solution
 runApplication potentialFoam -pName p_rgh