Added basic test for parse_headers()

t/Repo.t

@@ -14,5 +14,6 @@ my $stm = $repo->load_stm(stm=>'/release/rc.stm');
 &helper::dmup(stm=>$stm);
 ok($stm,            "stm is true");
 
+ok($stm->parse_headers(), "parse_headers() returns true");
 
 done_testing();