Add --template debugging.

This allows **-s -ttree** to see the template AST, which eases
debugging of complex templates.  It introduce an API change of
the tree interface needing to touch the lowdown options.

While here, considerably clean up the main manpages, introducing
a new section for metadata and cleaning up the standalone part.
This cleanup is due to the -s behaviour changes w/r/t the new
template functionality.

extern.h

@@ -24,9 +24,11 @@ struct	hentry {
 TAILQ_HEAD(hentryq, hentry);
 
 struct lowdown_meta
-		*lowdown_get_meta(const struct lowdown_node *, struct lowdown_metaq *);
+		*lowdown_get_meta(const struct lowdown_node *,
+			struct lowdown_metaq *);
 int		 lowdown_template(const char *, const struct lowdown_buf *,
-			struct lowdown_buf *, const struct lowdown_metaq *);
+			struct lowdown_buf *, const struct lowdown_metaq *,
+			int);
 
 int	 	 smarty(struct lowdown_node *, size_t, enum lowdown_type);
 

gemini.c

@@ -990,7 +990,7 @@ lowdown_gemini_rndr(struct lowdown_buf *ob, void *arg,
 			goto out;
 		if (!rndr(tmp, &metaq, st, n))
 			goto out;
-		rc = lowdown_template(st->templ, tmp, ob, &metaq);
+		rc = lowdown_template(st->templ, tmp, ob, &metaq, 0);
 	} else
 		rc = rndr(ob, &metaq, st, n);
 

html.c

@@ -1037,7 +1037,7 @@ rndr_root(struct lowdown_buf *ob, const struct lowdown_buf *content,
 	if (!(st->flags & LOWDOWN_STANDALONE))
 		return hbuf_putb(ob, content);
 	if (st->templ != NULL)
-		return lowdown_template(st->templ, content, ob, mq);
+		return lowdown_template(st->templ, content, ob, mq, 0);
 
 	TAILQ_FOREACH(m, mq, entries)
 		if (strcasecmp(m->key, "author") == 0)

latex.c

@@ -676,7 +676,7 @@ rndr_root(const struct latex *st, struct lowdown_buf *ob,
 	if (!(st->oflags & LOWDOWN_STANDALONE))
 		return hbuf_putb(ob, content);
 	if (st->templ != NULL)
-		return lowdown_template(st->templ, content, ob, mq);
+		return lowdown_template(st->templ, content, ob, mq, 0);
 
 	TAILQ_FOREACH(m, mq, entries)
 		if (strcasecmp(m->key, "author") == 0)

library.c

@@ -88,7 +88,7 @@ lowdown_render(const struct lowdown_opts *opts,
 		lowdown_term_free(rndr);
 		break;
 	case LOWDOWN_TREE:
-		c = lowdown_tree_rndr(ob, n);
+		c = lowdown_tree_rndr(ob, n, opts);
 		break;
 	default:
 		c = 1;

lowdown.h

@@ -447,7 +447,8 @@ int 	 lowdown_nroff_rndr(struct lowdown_buf *, void *,
 		const struct lowdown_node *);
 
 int 	 lowdown_tree_rndr(struct lowdown_buf *, 
-		const struct lowdown_node *);
+		const struct lowdown_node *,
+		const struct lowdown_opts *);
 
 void	 lowdown_latex_free(void *);
 void	*lowdown_latex_new(const struct lowdown_opts *);