- this stop problems caused by a "-case .." specification

  Previously  args.globalCaseName() + ".Ext"  resulted in silly names
  eg, "...png", or "surface-...stl"

Mark Olesen authored 15 years ago and Andrew Heather committed 15 years ago

- Locate user/site/shipped file with the semantics used in the
  ~OpenFOAM/fileName expansion

- Locate user/site/shipped file with the semantics used in the
  ~OpenFOAM/fileName expansion

- contains the name part of the FOAM_CASE environment variable

- similar to the #include directive, but does not generate an error if the
  file does not exist.

Note: opted for an explicit naming #includeIfPresent rather than #cinclude

  - 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