Support error exit codes in more cases

This patch makes the pprint and vgrind return error codes if generation of the typeset or filtered files fails. Its main purpose is supporting the simple install test feature provided by Homebrew formula, and it may also be useful if these scripts are themselves used in other scripts.

Fix minor errors in vgrindefs.src

cap_mkdb does not accept a language name without alternatives, so I
have added one for R.  In the Fortran 77 definition, some leading spaces
have been converted to tabs, and extraneous spaces at the end of lines
have been removed.

Add Fortran 77 and R support

This release adds ghfbsd's support for Fortran 77 and R as well as a few minor changes.

Vgrind for the 21st century (well, sort-of)

Update NetBSD vgrind with a modern build system BSD and macOS, adding a "pprint" script for modern use cases.

• Mention pprint in README.md

• Add cmake generated files to .gitignore

• Move the original Makefile and vgrind.sh off to a directory named
  ATTIC. They are useful enough during development (still!) that I want
  to keep them in the HEAD, but also a source of confusion. A BSD
  Makefile in the main project directory is an invitation to mischief.
  It can be accidentally run, creating more files in the main source
  directory, and might be trusted when it should not be. Likewise,
  vgrind.sh, which no longer works, may be run by accident, creating
  mayhem.