ENH: adjust infoSwitch to report host subscription (related to #531)

See merge request OpenFOAM-plus!150

- this compact form shows the subscription per host in the unsorted
  mpi order

      nProcs : 18
      Hosts  :
      (
          (node1 6)
          (node2 8)
          (node3 4)
      )

  This provides a succinct overview of which hosts have been
  subscribed or oversubscribed.

- The longer list of "slave.pid" ... remains available on the
  InfoSwitch 'writeHosts'

- the -dir option was added in commit c1c6243c to allow quick
  testing of documentation for a set of classes.
  This was largely replicated in commit 843d83117, but accepting
  multiple directories.

  Apply some of the same ideas here and avoid creation of a tmp file.

improve consistency in parsing primitives from strings

See merge request !146

Integration openfoam.org

See merge request !144

Previously:

  - bad command-line input such as -label 1234xyz would parse as a
    label (with value 1234) and the trailing junk would be silently
    ignored. This may or may not be appropriate. If the trailing junk
    looked like this '100E' or '1000E-' (ie, forgot to type the
    exponent), the incorrectly parsed values can be quite bad:

        label  = 32684
        scalar = 6.93556e-310

Now:

  - use the updated readLabel/readScalar routines that trigger a
    FatalIOError on bad input:

        --> FOAM FATAL IO ERROR:
        Trailing content found parsing '1234xyz'

        --> FOAM FATAL IO ERROR:
        Trailing content found parsing '100E'

   This traps erroneous command-line input immediately.

- Any trailing whitespace when parsing from strings or character buffers
  is ignored rather than being treated as an error. This is consistent
  with behaviour when reading from an Istream and with leading whitespace
  being ignored in the underlying atof/atod, strtof/strtod... functions.

- Allow parsing directly from a std::string instead of just from a 'char*'.
  This reflects the C++11 addition of std::stod to complement the C
  functions strtod. This also makes it easier to parse string directly
  without using an IStringStream.

- Two-parameter parsing methods return success/failure.
  Eg,

      if (readInt32(str, &int32Val)) ...

- One-parameter parsing methods return the value on success or
  emit a FatalIOError.
  Eg,

      const char* buf;
      int32Val = readInt32(buf, &);

- Improved consistency when parsing unsigned ints.
  Use strtoimax and strtoumax throughout.

- Rename readDoubleScalar -> readDouble, readFloatScalar -> readFloat.
  Using the primitive name directly instead of the Foam typedef for
  better consistency with readInt32 etc.

- Clean/improve parseNasScalar.
  Handle normal numbers directly, reduce some operations.

Note that now mirrorMesh does not delete empty patches anymore.

Feature paraview clouds

See merge request !145

- Can occur if the selected geometry does not actually exist.
  A non-critical bug since paraview catches this anyhow and
  just emits a warning message.

- previous only checked for clouds at the last instance and only
  detected lagrangian fields from the first cloud.

  Now check for clouds at all instances and detect all of their fields
  as well.

Feature surface field value operations

See merge request !141

Feature surface scaling

See merge request !139

- affects surfaceFieldValue, volFieldValue.

  Use 'none' (if desired) to explicitly suppress the weightField, but
  generally better to use a different operation.