Remove hive code

Hi Branky,

I have removed some Hive code from the current code base to archive better compatibility.

Removed code: OrcStruct.java, OrcSerde.java, OrcProto.java, OrcOutputFormat.java. The new implementation will use ObjectInspectors to access OrcStruct, and have a new OrcSchemeOutputFormat to deal with the output path issue.

Please help me review the change. Thanks!