auto: fix bug in Par(NL, NL) case

Was reversing the order of parallel composition. That would sill
preserve the semantics but it's harder to test against.
auto: fix bug in Seq(NL, NL) case

Similar problem that Par had, except in this case it affected
associativity.
auto: fix Par(NL, NL) and Seq(NL, NL) case

Wasn't propagating the cstr correctly. This commit however introduces
associativity problems.