- this provides a means to temporarily override the default settings
  and/or the prefs.{csh,sh} settings.

  bash:
      name=       -> unset name
      name=value  -> export name=value

  csh:
      name=       -> unsetenv name
      name=value  -> setenv name value

  eg,
      . <WM_PROJECT_DIR>/etc/bashrc WM_COMPILER=Gcc45 WM_MPLIB=
  to use gcc 4.5 and the default mplib

editing the respective settings files.

- foamEtcFile is used to find the files, thus follows the standard
  ~OpenFOAM/fileName expansion mechanism.

- exception calcType.H since it'll most likely be used for building
  applications anyhow

- use quailified names in more of the lagrangian code

- killed some tab indents in various places.

- change name of environment variable from $WM_OS -> $WM_OSTYPE
  as a better description

- Problem: changing between OpenFOAM versions with different
  WM_PROJECT_INST_DIR paths would leave the old paths in the env vars.

- TODO: etc/cshrc is rougned out, but needs work on the corresponding
  if-statement

  - avoid mkdir except for a few directories
  - grouped settings and added comments
  - minor bugfix: $FOAM_INST_DIR/linux64/bin was in path (pre OpenFOAM-1.5)
  - local (non-exported) variables in lowercase

  * prefix internal functions with _foam to prevent collisions
  * cleanup functions after use
  * centralized FOAM_VERBOSE info to etc/{bashrc,cshrc}