Fix silly naming mistake

Author: adamcik

netfields/__init__.py

@@ -0,0 +1,3 @@
+from netfields.managers import NetManger
+from netfields.fields import (InetAddressField, CidrAddressField,
+        MACAddressFormField)

netfilters/fields.py renamed to netfields/fields.py

@@ -2,7 +2,7 @@
 
 from django.db import models
 
-from netfilters.forms import NetAddressFormField, MACAddressFormField
+from netfields.forms import NetAddressFormField, MACAddressFormField
 
 class _NetAddressField(models.Field):
     empty_strings_allowed = False