Fix to_dict not converting enums to strings

Fixes #28

capnp/lib/capnp.pyx

@@ -735,6 +735,9 @@ cdef _to_dict(msg, bint verbose):
 
         return ret
 
+    if msg_type is _DynamicEnum:
+        return str(msg)
+
     return msg
 
 

test/test_struct.py

@@ -171,3 +171,11 @@ def test_set_dict_union(addressbook):
     person = addressbook.Person.new_message(**{'employment': {'employer': {'name': 'foo'}}})
 
     assert person.employment.employer.name == 'foo'
+
+
+def test_to_dict_enum(addressbook):
+    person = addressbook.Person.new_message(**{'phones': [{'number': '999-9999', 'type': 'mobile'}]})
+
+    field = person.to_dict()['phones'][0]['type']
+    assert isinstance(field, basestring)
+    assert field == 'mobile'