Hbase Put - Performance improvements

[claudiofusi]

To improve the performance of the Put operation with 0.9X Hbase client API level :

• consider disabling autoFlush(refer to http://hbase.apache.org/0.94/book/perf.writing.html)
• move the HTable creation to the initialization phase of the operator, instead of creating/closing the HTable for every tuple/batchSize

[natashadsilva]

Closing since we have added the enableBufferparameter to disable autoflush if needed.