Description
    Remove all .o files from the object directory tree corresponding to the
    current source derectory or remove only the .o file corresponding to the
    optionally specified [file].

Remove all .dep files from the object directory tree corresponding to the
current source derectory or remove only the .dep files referring to the
optionally specified [file].

This reverts commit c5bea524.

This reverts commit 2e1e671d.

- Also adjusted formatting of usage to match what argList generates

  - send error messages to stderr
  - added -h/-help options where some were missing
  - changed 3-space to 4-space indentation
  - where possible, allow multiple directories from the command-line

  - removed legacy foamDiffSourceList, foamPackChanged
  - added foamPackDoxygen for separate distribution of docs
    handles -prefix option
  - misc. cosmetic changes