simpleRho or limiting p.

Update pEq for close domains.

Modification on rhoPimpleFoam pEq's for handling rho thermo and incompressible EoS. Adding rho limiters if p is limited.
This is important when LTS stepping or large Co number is used.

Updating rhoBuoyantPimpleFoam to handle closed domain for rho thermo and incompressible Eos.
Consolidating chtMultiRegionSimpleFoam and chtMultiRegionFoam pEqs to use the same formulation as rhoBuoyantPimpleFoam and
rhoBuoyantSimpleFoam

2)Adapting divU in TEqn.H for compressibleInterDyMFoam and compressibleInterFoam
3)Re-instated sixDoFRigidBodyDisplacement as patch for pointFields. It allows to use a different fvDynamincMesh type
independently of the BC's

- these are compile-time constants and can be marked as such in C++11.

ENH: noiseModels - updated parallel usage (no longer needs proc dirs) and apply input data validation

Revert "sixDoFRigidBodyDisplacementPointPatchVectorField, uncoupledSixDoFRigidBodyDisplacementPointPatchVectorField: removed"

This reverts commit 942338b0.

COMP: unitConversion - using M_PI instead of pi to avoid compiltion error due to pi not evaluating to a constexpr

Feature surface feature extract

See merge request !110

ccm conversion bugfixes

See merge request !115

- was generally somewhat fragile. The main problem stems from the fact
  that several interfaces may be attached to a boundary. No trivial
  means of solving this without too much work for a feature that is only
  "nice-to-have".

- Programming convenience.
  Eg, cos(45_deg) vs cos(degToRad(45))

STYLE: conversions marked as constexpr and noexcept

- makes it possible to use list types other than UList.
  For example, UIndirectList<point>

- not yet release, but some of the API and file locations are closer
  to 1706 than to 1612. Needed, for example, for swak4foam.

- eg, swak4Foam uses it for NumericAccumulationNamedEnum

- allows simultaneously reordering and truncation of lists

STYLE: add const ref for UnaryPredicate parameter