- checkIn() was incorrectly conditional on the register state of the
  source object.

Partial patch from .org commit 6dc48b62d948

- was WM_PROJECT_API in the environment and FOAM_API in dictionaries.

  Make these both consistently FOAM_API.
  This is a non-breaking change, since the value of WM_PROJECT_API
  (added in 1812) and/or FOAM_API is purely informative.
  For the current correct values, always use

    * foamEtcFile -show-api
    * wmakeBuildInfo -show-api

- If using a non-clang compiler suite (gcc, intel, etc) the additional
  lbraries required for mesa with llvm pipelines may not be found.

  Provide a mesa_llvm configuration with in the 'vtk' config file.
  Can use the usual types of settings

     * mesa_llvm=llvm-4.0.1
     * mesa_llvm=none
     * mesa_llvm=system

- could be triggered if running in parallel, but requesting procIDs
  to be written with a non-parallel version of the writer.

- uses the value of foamVersion::api, which should be reliable.

- and support setting cmake_version within the paraview config files

- looks slightly messier without associative arrays, but improves
  portability. Should now also work with dash.

STYLE: support wmakeBuildInfo -cmp and -check options as equivalent

- they had an isType<> instead of isA<>() check

    Averages columns of cells for layered meshes.

    For each patch face, calculates the average value of all cells attached in
    the patch face normal direction, and then pushes the average value back
    to all cells in the column.

    Useful for channel-like cases where we want to average fields in the
    spanwise direction.

    Example of function object specification:
    columnAverage1
    {
        type        columnAverage;
        libs        ("libfieldFunctionObjects.so");
        ...
        patches     (front side);
        fields      (U p);
    }

    Where the entries comprise:
    \table
        Property     | Description               | Required    | Default value
        type         | type name: fieldMinMax    | yes         |
        patches      | list of patches to collapse onto | yes  |
        fields       | list of fields to process | yes         |
    \endtable