Major Description
Several packages have classes from multiple modules in the new layout.
In general, we should avoid this. Ideally, o.a.a.ipc would only exist in the avro-ipc.jar for example.
For 1.5.0, I'd like to move the easy stuff around to better correlate packages with modules.
This will cause API changes we need to document. Unfortunately, moving classes around is not something you can do gradually. Ideally these are isolated.