PAPI: Add MACAddress object wrapper for vl_api_mac_address_t

Change the definition of vl_api_mac_address_t to an aliased type.

Change-Id: I1434f316d0fad6a099592f39bceeb8faeaf1d134
Signed-off-by: Ole Troan <ot@cisco.com>
diff --git a/src/vpp-api/python/vpp_papi/vpp_serializer.py b/src/vpp-api/python/vpp_papi/vpp_serializer.py
index 418c024..d62e3a4 100644
--- a/src/vpp-api/python/vpp_papi/vpp_serializer.py
+++ b/src/vpp-api/python/vpp_papi/vpp_serializer.py
@@ -30,9 +30,10 @@
 logger = logging.getLogger(__name__)
 
 if sys.version[0] == '2':
-    check = lambda d: type(d) is dict
+    def check(d): type(d) is dict
 else:
-    check = lambda d: type(d) is dict or type(d) is bytes
+    def check(d): type(d) is dict or type(d) is bytes
+
 
 def conversion_required(data, field_type):
     if check(data):
@@ -101,7 +102,7 @@
             return b'', 0
         p = BaseTypes('u8', length)
         x, size = p.unpack(data, offset + length_field_size)
-        x2 = x.split(b'\0',1)[0]
+        x2 = x.split(b'\0', 1)[0]
         return (x2.decode('utf8'), size + length_field_size)