Add compiling packnet model, refactor modules to not duplicate loaders and trainers

packnet_tests.py

@@ -28,6 +28,10 @@ class PacknetTests(unittest.TestCase):
         # TODO: Anything else we can test here for validity?
         self.assertEqual(y.shape, out_shape)
 
+    def test_packnet(self):
+        packnet = p.make_packnet()
+        self.assertIsNotNone(packnet)
+
 
 if __name__ == '__main__':
     unittest.main()