Adding optional files to smallPoolFire2D to run using this model.
Taking out of the compilation of FSD combustion. It needs futher work to run using the new turbulent framework

This was causing same event number on both U and grad(U) which meant
that if one of the processors had different event number the trigger
of gradient caching would not be synchronised. Now instead the overflow
is detected in the regIOobject::upToDate function and handled consistently
(by assuming that the events of object will never differ by more than
labelMax/2)

- old convention was that on last time step it would only call end()
and not execute()
- however this meant that e.g. the functionObjectProperties file
did not get written
- and almost all functionObjects were doing an execute() inside of end()
- new convention: call execute() on last time step, just before doing end()

- Initial code supplied by CFD+Engineering
- Refactored and integrated into the code by OpenCFD

- Initial code supplied by CFD Software E+F GmbH
- Refactored and integrated into the new templated Turbulence structure
  by OpenCFD

References:

- kOmegaSSTDES model:
  Strelets, M. (2001)
  Detached Eddy Simulation of Massively Separated Flows,
  39th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV

- kOmegaSSTDDES model:
  Gritskevich, M.S., Garbaruk, A.V., Schuetze, J., Menter, F.R. (2011)
  Development of DDES and IDDES  Formulations for the k-omega
  Shear Stress Transport Model, Flow, Turbulence and Combustion,
  pp. 1-19

- kOmegaSSTIDDES model:
  Gritskevich, M.S., Garbaruk, A.V., Schuetze, J., Menter, F.R. (2011)
  Development of DDES and IDDES Formulations for the k-omega
  Shear Stress Transport Model, Flow, Turbulence and Combustion,
  pp. 1-19

It was not correctly interpolating faceZones which are on processor boundaries.
This caused difference between serial and parallel running. Fixes #16.

Included option to use the low Reynolds number correction, with a
default value of 'on'.  Further details can be found in the reference:

    Spalart, P. R., Deck, S., Shur, M.L., Squires, K.D., Strelets, M.Kh,
    Travin, A. (2006).
    A new version of detached-eddy simulation, resistant to ambiguous grid
    densities.
    Theor. Comput. Fluid Dyn., 20, 181-195.

Set using the entry:

    lowReCorrection on; // off

Some bcs (e.g. humidity) use an external transported field so this needs
to be registered asap.

For distributed data + running redistributePar some of the processors
might not have level0Edge. In this case the sync() routine should
fix this but it does require at least the master to have valid data.

- Initial code supplied by CFD Software E+F GmbH
- Refactored and integrated into the new templated Turbulence structure by
  OpenCFD
- To use the new convection scheme, add the library
  libturbulenceModelSchemes.so to the $FOAM_CASE controlDict

Object generates an indicator field for DES turbulence models to show
in which regions LES or RAS modelling is active.

SpalartAllmarasDES now derived from DESModel class

The signal handling can now be set and unset. This latter is important
for external libraries (e.g. VTK/OpenGL) that do not work with it.