Squashed commit of the following:
commit 4cdb99fb Author: Mathias Preiner <mathias.preiner@gmail.com> Date: Tue May 15 19:44:07 2018 -0700 Update status of unknown check-sat calls.
commit 4cdb99fb Author: Mathias Preiner <mathias.preiner@gmail.com> Date: Tue May 15 19:44:07 2018 -0700 Update status of unknown check-sat calls.