* guile-snarf-docs.in, guile-snarf-docs-texi.in: rewrite &
simplify.
* eval.c: all hash signs are in column 0.
* Makefile.am (guile_filter_doc_snarfage): build using
c-tokenize.c, not filter-doc-snarfage.c.
rearrange snarfing dependencies a bit.
* c-tokenize.lex: new file.
