AVRO-1474. C++ resolvind decoder doesn't work when reader schema has more fields than writer schema

git-svn-id: https://svn.apache.org/repos/asf/avro/trunk@1606545 13f79535-47bb-0310-9956-ffa450edef68
AVRO-1352. Schema for fixed types corrupted when writing out in JSON format

git-svn-id: https://svn.apache.org/repos/asf/avro/trunk@1606560 13f79535-47bb-0310-9956-ffa450edef68