Includes joint work with @abmclin, @pmatos, and @jessealama. original commit: 2649600c68ff57efb63d6d5d10c9d9f73368f59a
7.ss, scheme.1.in, comments of many files original commit: 06f858f9a505b9d6fb6ca1ac97234927cb2dc641
original commit: 47a210c15c63ba9677852269447bd2f2598b51fe