Add support for included and excluded records

`Included` and `Excluded` can be used to filter records for one or more specific provider(s). This can be extremely useful when certain record types are not supported by a provider and you want only that provider to receive an alternative record.

See also: https://github.com/github/octodns/issues/26

octodns/record.py

@@ -124,6 +124,8 @@ class Record(object):
 
         octodns = data.get('octodns', {})
         self.ignored = octodns.get('ignored', False)
+        self.excluded = octodns.get('excluded', [])
+        self.included = octodns.get('included', [])
 
     def _data(self):
         return {'ttl': self.ttl}