Removing println from OperationMerge
Merge pull request #449 from mattrjacobs/remove-merge-println

Removing println from OperationMerge
Fixed testOnErrorViaHasNext in issue #383
Removed the unnecessary 'catch' and 'fail'
Blocked 'hasNext' instead of 'next' until any notification arrives
Followed the iterator contract
Force 'hasNext' and 'next' throw the error once they have already thrown it before