started with forallp_existsp, forallp_notexistsnotp and notforallnotp_existsp.

Signed-off-by: Pepijn Kokke <pepijn.kokke@gmail.com>
made some progress in proving the other side of forall<->exists, but undecidability is a bitch.

Signed-off-by: Pepijn Kokke <pepijn.kokke@gmail.com>