product set local changes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Merge branch 'opt' of https://git01.codeplex.com/z3 into opt
Merge branch 'opt' of https://git01.codeplex.com/z3 into opt
basic primal/dual

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>