bug by me: forgot to make points affine before hashing them

bgn2/src/Bipoint.cpp

@@ -273,6 +273,8 @@ size_t TwistBipointHash::operator()(const TwistBipoint& x) const
 		retval[1] = 0;
 		infinity[1] = false;
 	}
+
+	affine_x.make_affine();
 	
 	for (int i = 0; i < 2; i++)
 	{