fix return macro, add warn function

* agen5/ag-text.def (WARN_FMT): for "warn" function
* agen5/expFormat.c (ag_scm_warn): implementation
* agen5/autogen.h (for_state_t): added fields to support RETURN
* agen5/funcFor.c (for_by_step): adjust for new context fields
  (for_each): likewise
  (free_for_context): rewritten to handle this stuff
* agen5/test/return.test: new test
tweak NEWS
minor tweaks
warn about using "test-main"
add insert-file function

Sometimes, it is just easier to insert the contents of a file
than to go through "shell" and "cat" it into the output.

* agen5/ag-text.def (LD_EXTRACT_BAD_READ): no longer used
* agen5/agUtils.c (open_trace_file): use "fserr" call instead of AG_ABEND
* agen5/expExtract.c (load_file): likewise
* agen5/funcEval.c (ag_scm_insert_file): new function to implement

plus documentation and testing changes to support this.
remove unused strings

* agen5/ag-text.def: many of the strings are no longer used.
  Also, in the shell initialization, ensure "set +o verbose"
  has been processed.
* agen5/agUtils.c (fswarn): new, for when fs errors are not fatal.
* agen5/defDirect.c (file_size): use it
  (doDir_include): use it
* agen5/expExtract.c (load_file): if fstat(3) fails, return errno
* agen5/funcEval.c (emit_insertion_file): use load_file()
* autoopts/tpl/cmd-doc.tlib: use new functionality
set release version
put man page sections in SEC subdirectory

Some platforms to no support in-memory file io.  These use the $tmp_dir
directory to stash temp files.  The "cmd-doc.tlib" template assumes
that all files in that directory are man page sections.  Oops.

* autoopts/tpl/cmd-doc.tlib: rework to avoid this
* other files: strictly cleanup
licensing & DASH shell tweak

* agen5/test/format.test: export AUTOGEN_DNE_DATE explicitly.
  DASH does not export when the assignment is on the same line
  as a shell function invocation.
* autoopts/tpl/*.pl: document the licensing of the perl scripts.