Ensure that statements are proven in right order

src/problem.rs

@@ -306,6 +306,7 @@ impl Problem
 	where
 		F: FnMut(&mut Statement) -> G,
 	{
+		// TODO: properly ensure that statements are proven in the right order
 		for section in self.statements.borrow_mut().iter_mut()
 		{
 			for statement in section.1.iter_mut()

src/problem/section_kind.rs

@@ -2,11 +2,11 @@
 #[derive(Clone, Copy, Eq, Ord, PartialEq, PartialOrd)]
 pub enum SectionKind
 {
-	CompletedDefinitions,
-	IntegrityConstraints,
 	Axioms,
 	Assumptions,
 	Lemmas,
+	CompletedDefinitions,
+	IntegrityConstraints,
 	Assertions,
 }