Reverted changes proposed in
http://openfoam.org/mantisbt/view.php?id=1548 as it adversely affects
fixed-value BCs and is formulated to fix an issue with an unphysical
case.  Further analysis of the handling of fixed pressure outlet
conditions as the Mach number approaches 1 is required.

Use the trace as the limiter function for both symmTensor and tensor to
bound the normal stresses rather than the shear stresses.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1751

Now consistent with the way the Courant number is calculated for other solvers

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1748

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1746

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1749

on the lambda of the film

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

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1636

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1157

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

pairPatchAgglomeration: Do not use the result agglomeratePatch if the return indicates it is not valid
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1157

Applying patches provided by Timo Niemi
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1636

Multi-species, mass-transfer and reaction support and multi-phase
structure provided by William Bainbridge.

Integration of the latest p-U and face-p_U algorithms with William's
multi-phase structure is not quite complete due to design
incompatibilities which needs further development.  However the
integration of the functionality is complete.

The results of the tutorials are not exactly the same for the
twoPhaseEulerFoam and reactingTwoPhaseEulerFoam solvers but are very
similar.  Further analysis in needed to ensure these differences are
physical or to resolve them; in the meantime the twoPhaseEulerFoam
solver will be maintained.

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 additional bug-report http://www.openfoam.org/mantisbt/view.php?id=1544

Resolves additional request in http://www.openfoam.org/mantisbt/view.php?id=1544

twoPhaseEulerFoam/interfacialModels/heatTransferModels/sphericalHeatTransfer: new heat-transfer model

Model which applies an analytical solution for heat transfer from the
surface of a sphere to the fluid within the sphere.

Provided by William Bainbridge

This is necessary to guarantee consistency between the residualAlpha
used for drag and buoyancy in a multi-phase system

to allow combustionModel to be used with more general forms of multi-phase

by naming fields including the phase name is needed

i.e. without the group suffix.

Patch provided by William Bainbridge

Applied as a correction pre-factor to the viscosity obtained from a
run-time selectable base-model.

filmViscosityModel/thixotropicViscosity/thixotropicViscosity: Remove the spurious mask and correct the blending

Resolves bug-report http://openfoam.org/mantisbt/view.php?id=1730

Also removed the underlying structure for "alwaysApply" from fvOption

fixedTemperatureConstraint,effectivenessHeatExchangerSource: Set the field name to that of the energy
field from which the temperature is obtained

Removes the need for the 'alwaysApply' hack.

limitTemperature: Set the field name to that of the energy field from which the temperature is obtained
Removes the need for the 'alwaysApply' hack.

writeData is not yet completely consistent with read.