Automaton VCG graph output.

Automaton VCG graph output.
Using option ``-g'' or long option ``--graph'', you can generate
a gram_filename.vcg file containing a VCG description of the LALR (1)
automaton of your grammar.
* src/main.c: Call to print_graph() function.
* src/getargs.h: Update.
* src/getargs.c (options): Update to catch `-g' and `--graph' options.
(graph_flag): New flag.
(longopts): Update.
(getargs): Add case `g'.
* src/files.c (graph_obstack): New obstack struct.
(open_files): Initialize new obstack.
(output_files): Saves graph_obstack if required.
* src/files.h (graph_obstack): New extern declaration.
* src/Makefile.am: Add new source files.