* move parquet-extensions from contrib to core, adds new hadoop parquet parser that does not convert to avro first and supports flattenSpec and int96 columns, add support for flattenSpec for parquet-avro conversion parser, much test with a bunch of files lifted from spark-sql
* fix avro flattener to support nullable primitives for auto discovery and now only supports primitive arrays instead of all arrays
* remove leftover print
* convert micro timestamp to millis
* checkstyle
* add ignore for .parquet and .parq to rat exclude
* fix legit test failure from avro flattern behavior change
* fix rebase
* add exclusions to pom to cut down on redundant jars
* refactor tests, add support for unwrapping lists for parquet-avro, review comments
* more comment
* fix oops
* tweak parquet-avro list handling
* more docs
* fix style
* grr styles
Jonathan Wei
Clint Wylie