Fix order of bindings in let expressions.
Fix order of bindings in let expressions.

nathanielbaxter/libminizinc,nathanielbaxter/libminizinc,tias/libminizinc,jjdekker/libminizinc,jjdekker/libminizinc,nathanielbaxter/libminizinc,tias/libminizinc,jjdekker/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc