Pig and Hive cannot read repeated groups written with parquet-protobuf

parquet-hive and parquet-pig make assumptions about list schemas that are not compatible with the more compact schemas generated by parquet-protobuf. This bug was discussed in more detail on https://github.com/Parquet/parquet-mr/issues/354

**Reporter**: [Nathan Howell](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=NathanHowell)

_{**Note**: *This issue was originally created as [PARQUET-14](https://issues.apache.org/jira/browse/PARQUET-14). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start by reading the list-schema handling in parquet-hive and parquet-pig, then use the discussion in issue 354 to understand how parquet-protobuf produces compact repeated-group schemas. Done means both readers accept those schemas without breaking existing list-schema handling; the payload names no specific files or tests, so those entry points must be located first.

Written by the indexing model from the issue text.