- add some notes about 'git submodule' in modules/README.md

- adjust comment formatting to reduce clutter

- relocate WM_COMPILER_ARCH, WM_COMPILER_LIB_ARCH from
  etc/{bashrc,cshrc} to etc/config.{csh,sh}/settings since these
  should not be changed by the user anyhow.

- Use gcc/g++ as common base and specialize afterwards (to reduce
  duplication)

- adjust format of WM_PROJECT_SITE fallback to allow for easier
  automated edits

- easier to ensure that flags are consistent

- primary points for an external user are the polyMesh constructor

- add config info for gcc-7.3.0

COMP: intel-2017. Ignore unknown pragmas. Disambiguate method resolution.

- forward command-line arguments for paraview, where they may also be
  evaluated (cshrc, POSIX shell)
  Eg,
      . etc/bashrc ParaView_VERSION=5.4.1-mpipy
      source etc/cshrc ParaView_VERSION=5.4.1-mpipy

- export library path for gmp/mpfr from CGAL config files.
  This is required when non-system gmp/mpfr libraries are being
  used, but not using a ThirdParty compiler installation.

- automatically handle lib/ vs lib64/ (eg, for central installations)
  for packages such as boost, CGAL, etc. While the ThirdParty
  compilation of these will normally land in lib64/, this may not be
  the case when they are supplied by another means.

- reworked the handling of foamEtcFile and foamCleanPath for less
  clutter in the configuration files.
  Added the bin/tools/lib-dir script to handle logic that is
  too complex to easily manage in csh.

- for Darwin, mention that clang is the only compiler configured

- adjust comments

- the (global) associative array requires bash >= 4.2

- the cray C/C++ compilers appear to be option-compatible with gcc.

- no wmake rules for 32bit builds (deemed to be unnecessary)

- use complete -o filenames, dropped -o nospace to make it more responsive.

- restructure completion code to use a unified backend, which makes it easier
  understand, maintain and re-use.

- foamCreateBashCompletions now simply outputs to a stdout, and allows
  quick generation of completion of single applications.

- add -fileHandler completion in anticipation of future changes there.

- relocated as etc/config.s/bash_completion to prevent inadvertently
  having two versions (.com, .org) installed at the same time.

- allows configuration without an environment variable.
  For compatibility still respect FOAM_SIGFPE and FOAM_SETNAN
  env-variables

- The env-variables are now treated as true/false switch values.
  Previously there was just a check for env exists or not, but this
  can be fairly fragile for a user's environment.

- minor cleanup of bash completion script

- suppress error messages that appear with zsh.
  According to unset(1p), 'unset -f' unsets a function.
  If the function was not previously defined, this is a no-op.
  This is similar for zsh, but there it emits a warning if the
  function was not previously defined.

- avoid 'local' in functions sources from etc/bashrc.
  ksh does not support this.

- use 'command' shell builtin instead of 'type'.
  Seems to be more consistent between shell flavours.

- this implies that jobControl is a user-resource for OpenFOAM.
  It was previously located under $WM_PROJECT_INST_DIR/jobControl,
  but few users will have write access there.

- an unset FOAM_JOB_DIR variable is treated as "~/.OpenFOAM/jobControl",
  which can partially reduce environment clutter.

- provide argList::noJobInfo() to conveniently suppress job-info on an
  individual basis for short-running utilities (eg, foamListTimes) to
  avoid unneeded clutter.

- permit SYSTEMMPI user adjustments via
      etc/config.{csh,sh}/mpi-system
  This can be a convenient place for setting up SYSTEMMPI for OpenFOAM
  without adjusting bashrc, prefs.sh ...

- add a USERMPI type. This represents any generic mpi implementation.
  The user is responsible for supplying an appropriate
  wmake/rules/General/mplibUSERMPI file and managing all settings.

  This type of setup can be useful in combination with specific build
  systems (SPACK, EASYBUILD, etc) or module systems for which the MPI
  variant is part of the installed configuration.

- cleanup variables last in etc/bashrc for a clean exit code

- this allows the sys-admin to provide base values independent of any
  WM_PROJECT_SITE value.

Resolves patch request https://bugs.openfoam.org/view.php?id=2490

- handle sourcing bashrc with a relative path (issue #383)
- handle sourcing from bash and zsh.
  Still need manual intervention when sourcing dash, sh, or ksh.
- replace grep in etc/cshrc with sed only
- logical instead of physical path for WM_PROJECT_DIR (issue #431).
  Doesn't seem to be possible for csh/tcsh.

  * Continue using physical locations when comparing directories,
    but not for the top-level FOAM_INST_DIR, WM_PROJECT_DIR.

- relocate WM_CC, WM_CXX overrides from etc/config.*/compiler
  to etc/config.*/settings to ensure that they are left untouched
  when etc/config.sh/compiler is sourced while making third-party
  packages (eg, gcc, llvm, CGAL).

- provide fallback FOAM_TUTORIALS setting in RunFunctions

STYLE: remove "~OpenFOAM" fallback as being too rare, non-obvious

- easier to test or use different versions

- change WM_CXXFLAGS to -std=c++11 instead of -std=c++0x

Can now use this:
    _foamSourceEtc config.sh/scotch
    _foamSourceEtc config.csh/scotch

instead of this:
    _foamSource $($WM_PROJECT_DIR/bin/foamEtcFile config.sh/scotch)
    _foamSource `$WM_PROJECT_DIR/bin/foamEtcFile config.csh/scotch`

In the bash/sh version, leave the _foamSource function for now, since
ThirdParty is still relying on it.

STYLE: elminate while-loop for _foamAddPath etc since this type of
construct isn't readily possible for csh and isn't being used anywhere.

- bump ADIOS version to 1.11.1

- makes it easier to switch between mpi implementations (eg, openmpi, intelmpi etc)

- add comment about compiler setting for KNL

- sometimes used for off-screen rendering.
  Only add to library-path when they are actually available

- the configuration settings can be used for the third-party build,
  but the configuration is not yet actively enabled in
  etc/bashrc, etc/cshrc

Resolves request http://bugs.openfoam.org/view.php?id=2367

- consistently use SYSTEMOPENMPI for both sh and csh versions
  (inadvertently changed in ee5251a7).