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/incompressible/pimpleFoam/TJunctionFan/Allrun

@@ -11,7 +11,7 @@ runApplication blockMesh
 # Create faceZones for baffles and fan
 runApplication topoSet
 
-cp -r 0.org 0
+cp -r 0.orig 0
 
 # Create wall and cyclic baffles and the fields on them
 runApplication createBaffles -overwrite