- Write the individual contents, without a surrounding 'boundaryField'
  block. Similar to what dictionary::writeEntries() offers.

- Can currently have a periodic restart, but for simulations with a
  known run-up, it can be useful to have a specific time to restart
  the averaging.

- Note that the restartTime acts as a 'single-shot'. If the
  restartTime is already in the past when a simulation is started, it
  is ignored. If, during a simulation, the restartTime is crossed, it
  will be triggered and then set itself to be ignored in the future.

- On the first call, ParaView_DIR is unset and thus the clean-path
  fails with the warning "ParaView_DIR: Undefined variable."

  This looks messy, but is of no _major_ consequence since paraview
  doesn't need to be removed anyhow. The only slight risk is that the
  path to a third-party cmake might not be cleaned.

- Patch as per Bruno's suggestion.

- It is incorrect to prefix the assignment with an 'export' since this
  automatically marks the overall command as successful and circumvents
  the fallback.

  There is no simple way to have proper behaviour when sourced with a
  local directory path, but at least it now uses the fallback.

  It is still easy to wreak the mechanism with valid but confusing input.
  For example,

     ". /path/to/openfoam/etc/././bashrc"

  The only real certainty is that "${BASH_SOURCE%/*}"
  should point to the 'etc/' directory. In which case,

      cd ${BASH_SOURCE%/*}    # <- now in the etc/ directory
      pwd=$(pwd -P)           # <- fully-qualified path to etc/
      pwd=${pwd%/*/*}         # <- up two parent levels

  - This works with ". ./bashrc", but fails with ". bashrc"
    (probably not so common).
  - Con: The construct requires an additional sub-shell.

- include cleanup of other postProcessing directories:
  * Ensight, EnSight, ensightWrite

- don't need to remove files that cleanSnappyFiles already removed:
  * 0/cellLevel 0/pointLevel

- bundle removal of constant/ items together:
  * constant/cellDecomposition constant/polyMesh constant/tetDualMesh

correct case re-start

- In the foundation version they introduced a construct to handle
  the transition from 'wmRefresh' as an alias to 'wmRefresh' as
  a shell function. This transition is unnecessary for OpenFOAM+
  since 1606 used wmREFRESH (not wmRefresh) as an alias.

  For portability it is important to avoid this non-POSIX
  "type -t". It causes issues with dash and with zsh
  (mentioned in issue #277).

        type -t dash  ->   -t: not found
        type -t zsh   ->  zsh: bad option: -t

Note: zsh users may still noticed other problems.
For example, the POSIX 'unset -f' normally has no output, but in zsh
it reports an error and has exit code 1 if the function was not
previously defined. Whereas in POSIX (including bash, dash) it only
returns non-zero if the name(s) could not be unset.

Patch contributed by Mattijs Janssens
Resolves bug-report http://bugs.openfoam.org/view.php?id=2303

Patch contributed by Mattijs Janssens

Patch contributed by Bruno Santos
http://bugs.openfoam.org/view.php?id=2306