Also moved global classes which should be in the Foam namespace into it.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1514

turbulenceModels/RAS/SSG: Added Speziale, Sarkar and Gatski pressure-strain based Reynolds-stress turbulence model

classes in the DebugSwitches sub-dictionary of system/controlDict

src/TurbulenceModels/incompressible/turbulentTransportModels/RAS/kkLOmega: Corrected errors in implementation and from original paper according to
    Furst, J. (2013).
    Numerical simulation of transitional flows with laminar kinetic energy.
    Engineering MECHANICS, 20(5), 379-388.

Thanks to Jan-Niklas Klatt for analysing problems with and correcting
the implementation and testing corrections to the model proposed by
Furst.

This is as temporary fix pending the completion of the selectable thermal transport layer

term to the more commonly used form of Henkes, R.A.W.M., Van Der Vlugt, F.F. & Hoogendoorn, C.J. (1991).

Added references to the generalized gradient diffusion model

Now using the Daly-Harlow generalized gradient diffusion model