Initial implementation of flume graphite sink.

The graphite sink sends annotations with duration to graphite.
Update documentation to refer to version 2.0.1 instead of 2.0
Update batchSize parameter name to batchsize to be inline with other parameters (all lower case).
Update documentation to lower batchsize of ZipkinSpanCollectorSink.

Batch size was set to 100 but this does not work if you use memory
channel with default configuration. By default memory channel also uses
a batch size of 100. Sink should commit in smaller batches as channel
otherwise channel flow over and throws exceptions.