BUG: Added missing #include. See #600

tutorials/incompressible/pimpleFoam/laminar/planarPoiseuille/validation/WatersKing/WatersKing.C

@@ -45,6 +45,7 @@ Description
 #include "fvCFD.H"
 #include "singlePhaseTransportModel.H"
 #include "turbulentTransportModel.H"
+#include "IFstream.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //