Cartesian subCelling of collision cell implemented.  Need to check the impact on performance and results

Changed way of populating database for dsmcFieldCalc.  Added correctBoundaryConditions() to sigmaTcRMax on initialisation

Created new functionObject for dsmcFields, renamed post processing utility dsmcFields to dsmcFieldsCalc and calling function object from there.

Added an if (cR < SMALL) guard to VHS sigmaTcR calculation.  Giving each processor a different random number generator seed, otherwise they follow the same sequence and are not independent.  Tnis is a practical problem because they were producing molecules with the same velocity in neighbouring cells on different procs which then collided and caused a floating point error because they had equal velocities.

Added equipartition internal energy distribution sampling function and calling on particle intialisation, Maxwellian wall collision and free stream injection.  Interface with WallInteractionModel modified to pass a scalar& for the internal energy and a label to specify the typeId.

Averaging does not need to be weighted if the fields being averaged are extensive - they weight themselves automatically. Recording momentum and energy denisty, and averaging them, then once decent averaged fields exist, using the new dsmcFields utility to create the intensive fields: UMean and TMean (translational, internal and overall).

Change of plan - fields will be stored or referenced only at the solver level and tmps will be returned from the clouds to give them their instantaneous values.  Only T and U will be supplied to the dsmcCloud, as before, to provide boundary conditions. Added required field calculation functions.  Taking care about what is measured - a U field requires sum(momentum)/sum(mass) per cell - cells can have zero particles in them, hence divide by zero problems.  Averaging the momentum field and the rhoM field, and constructing the velocity by dividing the averages as a post-processing stage is a safer and more physcially correct method.

- regIOobject: don't re-register an unregister object on rename/assignment
- Hasher: split-off HasherInt with uint32_t specializations
- IOobject: writeBanner/writeDivider return Stream for easier chaining.

... also dropped some namespace bracketing while I was at it.

Added new fields to solver and basic calculation of momentum and energy change on wall impact.  Need to add references to new fields to DsmcCloud and constructors, all references are to be non-const as the field calculation will occur inside the DsmcCloud.

Properly random distribution of particles across inflow patch faces.  Modified info() reporting to average per-molecule energy and momentum - more useful.

- this seems to be the most sensible solution.
  The changed time stamps on the links doesn't seem to bother make at all.

- If the underlying type is contiguous, FixedList hashes its storage directly.
- Drop labelPairHash (non-commutative) from fvMeshDistribute since
  FixedList::Hash does the right thing anyhow.
- Hash<edge> specialization is commutative, without multiplication.
- Hash<triFace> specialization kept multiplication (but now uLabel).
  There's not much point optimizing it, since it's not used much anyhow.

Misc. changes

- added StaticAssert to NamedEnum.H
- label.H / uLabel.H : define FOAM_LABEL_MAX, FOAM_ULABEL_MAX with the
  values finally used for the storage.  These can be useful for pre-processor
  checks elsewhere (although I stopped needing them in the meantime).

Added InflowBoundaryModel submodel with NoInflow and FreeStream models.  Free stream inserts particles at a specified patch.  Currently inserting particles half way along the face centre to cell centre line - will randomise.   Fixed label/scalar inconsistency between declaration and accessors of nParticles.

	modified:   finiteVolume/cfdTools/general/MRF/MRFZone.C
modified:   finiteVolume/cfdTools/general/MRF/MRFZone.H
	modified:   ../tutorials/incompressible/MRFSimpleFoam/mixerVessel2D/constant/MRFZones

Added Larsen Borgnakke internal energy redistribution and all supporting variables and function calls.  Added energy and momentum monitoring functions.  Added U and T fields to be used for boundary conditions and field measurement. Modified constructors accordingly.  Now reading dsmcInitialiseDict in the Cloud, not the application.  Initialisation dict now reads a subdict of <species keyword> <number density> entries.

- not much speed difference between SuperFastHash and Jenkin's lookup3 but
  both are 5-10% faster than what is currently implemented in Foam::string,
  albeit inlining probably helps there.

- TODO: integration with existing infrastructure

http://openfoam.cfd-online.com/cgi-bin/forum/show.cgi?126/10948

Moved call to buildCellOccupancy() to within collisions.  Was calling before move() had been called, so some particles were changing processor when running in parallel and invalidating the pointers.