Initial support for Avro.
Remove unchecked generics warnings.
Honor repetitions correctly.
Add Binary.fromByteBuffer method.
Remove unnecessary level of grouping for array.
Fix creation of arrays and maps in converters.
Remove incorrect record initialization to compensate for broken support for nested records (not yet fixed).
Create generic Parquet reader and writer for object records.
Avoid copying bytes if ByteBuffer is array-based.
Avoid double conversion of bytes for Avro Utf8 instances.
Add test for nested records following fix in 61d5170844aaf611555a0dd63c5e24af08acf1c8
Remove -Xlint:unchecked flag from the build for the moment as it causes CI to fail.
Merge pull request #26 from tomwhite/avro

Initial support for Avro.
Thanks @tomwhite