Add NASNet-Large model

Author: rwightman

timm/models/__init__.py

@@ -5,6 +5,7 @@
 from .dpn import *
 from .senet import *
 from .xception import *
+from .nasnet import *
 from .pnasnet import *
 from .gen_efficientnet import *
 from .inception_v3 import *