Adding clone member functions to motion solvers

- A preliminary minor adjustment only.

- Can occur with some user names, or mounted paths.
  Resolve by using '?' for the separation character.

  Since '?' is a shell-glob, it is highly unlikely to occur appear in
  filenames.  Additionally, it is not a meta-character in standard sed,
  nor in the GNU extension (which uses '\?').

- Superfluous #include "FieldFunctions.H" provokes warnings/errors
  with newer gcc.

changed flag which caused infinite while loop. Background info:
- findCellZoneTopo tries to find for all named surface intersections
which side of the face is in the faceZone
- i.e. it tries to make the cellZone consistent with the faceZone
(to fix small problems)
- this had some logic to assign the neighbour cellZone to the owner cellZone
- which didn't check for the neighbour being the same value as the owner
- but still set a 'changed' flag which caused the loop to never end.

ENH: wallDist - added option to evaluate every XXX steps

Added functionality to update the wall distance every XXX steps

Note: only applies to movePoints() - topology change bypasses the update interval and triggers a re-calculation
Syntax:
```
wallDist
{
    method          ...
    updateInterval 5; // optional - default is 1
}
```

Test case: [mixerVesselAMI2D.tgz](/uploads/c0bee1decc0337018272f3566b6a4416/mixerVesselAMI2D.tgz)

See merge request !62

All of the access methods for autoPtr include validity checks and will
fail if the underlying point is NULL. In some cases, however, we'd
like to retain the automatic deletion mechanism, but still address a
nullptr. This is mostly for cases in which a file-stream should be
allocated, but only on the master process. For these cases we'd still
like to pass through and reference the underlying pointer (eg, to
obtain the correct method call) without tripping the pointer check
mechanism. If we attempt to use the ptr() method, the autoPtr memory
management is bypassed and we risk memory leaks.

Instead provide an alternative mechanism to obtain the raw underlying
pointers/references. Use rawPtr() and rawRef() for these potentially
useful, but also potentially dangerous, operations.

- Normally use '()' to deference. This has extra safety and issues a
  fatal error if the underlying pointer is not valid.

  However, in some cases we are happy with getting a null reference.
  The refOrNull() method returns the reference without any checking.

  Usage example:

      autoPtr<OFstream> osPtr;
      if (Pstream::master())
      {
          osPtr.reset(new OFstream(...));
      }
      writeViaMaster(osPtr.refOrNull());

      - The writeViaMaster() call takes an OFstream reference,
        but this is only used directly on the master.
        The slaves will pass things through to the master.

- can be used to loop over all enumerations in the order of definition.

- Similar to ensight converters (issue #240),
  improve speed for detection of lagrangian clouds.

- provide a -noLagrangian option for symmetry

- Less looping when detecting lagrangian clouds and their fields.

- Avoid using Time::setTime() and IOobjectList in tight loops.
  They both kill performance immensely.

ENH: provide a -noLagrangian option to foamToEnsight and foamToEnsightParts
for even more control.

- More informative than a horizonal line, can help when debugging.

STYLE: remove unused write field methods from ensightParts

- The new field needs initialization with a dimensioned<Type> not just
  the dimensionSet.

- The new field was also incorrectly being registered, which could
  cause issues later.

- affects foamToEnsightParts, sampled surfaces

- Use ensightPTraits mechanism throughout to avoid this issue

Old code:
    Found 10990 time steps
    Search for moving mesh ... no moving mesh detected.
    Startup in 329.09 s

Updated:
    Found 10990 time steps
    Search for moving mesh ... no moving mesh detected.
    Startup in 1.6 s

- Cause was checking "polyMesh/points" via an IOobject.
  Short-circuit with a check for a polyMesh/ directory first.

  Limit the check to the master-node as well to further reduce
  load on the file-system.

------------------------------

ENH: improve per-step conversion times for foamToEnsight.

Old code:
    Converting 11001 time steps
    Time [0] = 0       Wrote in 1.53 s
    Time [1] = 1       Wrote in 1.52 s
    ...
    Time [100] = 100   Elapsed time 205.35 s

Updated:
    Converting 11001 time steps
    Time [0] = 0       Wrote in 1.4 s
    Time [1] = 1       Wrote in 0.07 s
    ...
    Time [100] = 100   Elapsed time 42.4 s

- Speedup by hashing test results from the first conversion step
  instead of checking each time.

  Check data on all nodes to avoid problems with incomplete writes.

------------------------------

BUG: moving mesh detection failed for foamToEnsightParts

- adjusted to agree with updated foamToEnsight

------------------------------

Note:

- foamToEnsightParts (serial) still has about twice the throughput of
  foamToEnsight.

BUG: output field name instead of field (fixes #224)



See merge request !59

- bugfix (empty patches), and added detection of steady-state
  scheme.

Caveat: when called via execFlowFunctionObjects will always produce a
  zero field, since the oldTime field is not available for this mode.