Batch Puts and Deletes up together into 1 flush.

Use the same queue for pending Puts and Deletes instead of batching Puts and
sending Deletes one at a time.

This is the same functional change as the 'batched-deletes-and-puts' branch
in bagheera's HBaseSink.
Add the 'batchsize' command line param.

Should end up the same as the 'cdh4' branch.
Merge pull request #6 from mozilla-metrics/batched-deletes-and-puts

Batched deletes and puts