- Introduce SerializationKey strategy abstracting generation of object key
- Introduce SerializationFormat abstracting specific write-of-objects strategy
- Support Avro as a schema used by SequenceFile serialization
- Bump up avro-mapred version to latest 1.7.2 and use AvroSerialization class designed
to be used within SequenceFile serialization framework.
Rename HdfsWrite to HdfsWriter with conform to other Writer abstractions.