Serialized.setFile: use file ref instead of pointer for safety

src/ifcwrap/IfcGeomWrapper.i

@@ -350,7 +350,7 @@ public:
 		serializer_->finalize();
 	}
 
-	void setFile(ifcopenshell::file* file) override {
+	void setFile(ifcopenshell::file& file) override {
 		serializer_->setFile(file);
 	}
 
@@ -405,7 +405,7 @@ private:
 		$self->finalize();
 	}
 
-	void setFile(ifcopenshell::file* file) {
+	void setFile(ifcopenshell::file& file) {
 		$self->setFile(file);
 	}
 }
@@ -1256,7 +1256,7 @@ ifcopenshell::geometry::taxonomy::item::ptr try_upcast(PyObject* obj0, swig_type
 %}
 
 %inline %{
-	IfcGeom::ConversionResultShape* nary_union(PyObject* sequence) {
+	IfcGeom::ConversionResultShape* nary_union(PyObject* sequence) {
 		std::vector<const CGAL::Nef_polyhedron_3<CGAL::Epeck>*> nefs;
 		for(Py_ssize_t i = 0; i < PySequence_Size(sequence); ++i) {
 			PyObject* element = PySequence_GetItem(sequence, i);