Create Accismus output formats

[keith-turner]

Since Percolator is designed for incremental processing, it will need to to be initialized via map reduce. A file output format that creates rfiles containing data in the Accismus format that can be bulk imported would be one way to enable this. This would wrap the AccumuloFileOutputFormat.

Additionally, AccumuloOutputFormat could be wrapped to allow users to write directly to an Accumulo table using the Accismus data format.

Need to document how these differ from the map reduce output that runs load transactions.