repolist: add owner-filter

This allows custom links to be used for repository owners by
configuring a filter to be applied in the "Owner" column in the
repository list.
diff --git a/filter.c b/filter.c
index 270f009..9f433db 100644
--- a/filter.c
+++ b/filter.c
@@ -38,12 +38,14 @@
 	reap_filter(ctx.cfg.commit_filter);
 	reap_filter(ctx.cfg.source_filter);
 	reap_filter(ctx.cfg.email_filter);
+	reap_filter(ctx.cfg.owner_filter);
 	reap_filter(ctx.cfg.auth_filter);
 	for (i = 0; i < cgit_repolist.count; ++i) {
 		reap_filter(cgit_repolist.repos[i].about_filter);
 		reap_filter(cgit_repolist.repos[i].commit_filter);
 		reap_filter(cgit_repolist.repos[i].source_filter);
 		reap_filter(cgit_repolist.repos[i].email_filter);
+		reap_filter(cgit_repolist.repos[i].owner_filter);
 	}
 }
 
@@ -425,6 +427,10 @@
 			argument_count = 2;
 			break;
 
+		case OWNER:
+			argument_count = 0;
+			break;
+
 		case SOURCE:
 		case ABOUT:
 			argument_count = 1;