Feature/2.10.5/batch event processor sequencing

This moves the update of the BatchEventProcessor's Sequence into the main eventHandler delegation loop, so rather than updating the sequence after processing a (potentially) larg number of sequences, we update it every time we process a sequence.   

Is there any reason why this would not be a good idea?

I realize this pull req is against the 2.10.4 version of the code, and that Disruptor is in the 3.3 version(s) now, but the 3.3 code does the same thing with respect to this change that the 2.10 code does.  This could easily(ish) be pulled into the 3.3 code base, but unfortunately my application is still stuck using 2.10, so that is what I based the change on.