SpalartAllmarasDES now derived from DESModel class

Updated objects
- corrected Peclet number for compressible cases
- propagated log flag and resultName across objects

New function objects
- new fluxSummary:
  - calculates positive, negative, absolute and net flux across face
    zones
- new runTimeControl
  - abort the calculation when a user-defined metric is achieved.
    Available options include:
    - average value remains unchanged wrt a given threshold
    - equation initial residual exceeds a threshold - useful to abort
      diverging cases
    - equation max iterations exceeds a threshold - useful to abort
      diverging cases
    - min/max of a function object value
    - min time step exceeds a threshold - useful to abort diverging
      cases
- new valueAverage:
  - average singular values from other function objects, e.g. Cd, Cl and
    Cm from the forceCoeffs function object

This bc was in compressible turbulence library which made it dependent
on liquidProperties. It was moved to a separate library since it is only
used in a single tutorial.

ENH: Adding humidityTemperatureCoupledMixed BC and directionalPressureGradientExplicitSource and the corresponding tutorial
tutorials/heatTransfer/chtMultiRegionFoam/windshieldCondensation

Now consistent with constructors.

to allow the turbulent energy transport properties to be updated for
every energy solution if required.

Added correctEnergyTransport() call to reactingTwoPhaseEulerFoam

so that the specification of the name and dimensions are optional in property dictionaries.

Update tutorials so that the name of the dimensionedScalar property is
no longer duplicated but optional dimensions are still provided and are
checked on read.

Also removed __GNUC__ conditional compilation statements which are no
longer needed.

construction of the phases is not complete

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1745

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1741

if it depends on the availability of the physical properties of both
phases as the construction of the phase-system may not be complete.

Resolves bug-report http://openfoam.org/mantisbt/view.php?id=1704

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1696

Resolved part of bug-report http://www.openfoam.org/mantisbt/view.php?id=1690

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1673

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1659

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1658

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1638

mixtureKEpsilon: Changed bounded non-conservative transport flux to be volumetric rather than mass-based
Avoids numerical problems caused by large density gradients, particularly around the interface.
Allows the use of higher-order differencing for km and epsilonm

Added the pressure dependent part of the entropy from the equation of
state to that returned by the thermo entropy function.

TODO: Add entropy defect to the PengRobinsonGas::s(p, T) function.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1411