AVRO-1544. Java: Fix GenericData#validate for unions with null.  Contributed by Matthew Hayes.

git-svn-id: https://svn.apache.org/repos/asf/avro/trunk@1615764 13f79535-47bb-0310-9956-ffa450edef68
C#: Add support for RPC over HTTP.  Contributed by Dmitry Kovalev.

git-svn-id: https://svn.apache.org/repos/asf/avro/trunk@1615768 13f79535-47bb-0310-9956-ffa450edef68