Articles/#380 reply reply to originator differences

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@Particular/documentation can you review?
@indualagarsamy That is not so easy as I would have expected :-|

I built a new sample using meaningful names so that the output was not crowded with Endpoint1, 2 etc..but:

* seems that there is no way to export a diagram from SI, not that I know at least;
* the diagram is really self-explanatory but there is no mention of Reply and ReplyToOriginator that are technical details not relevant for the diagram itself;
* the diagram is enormous with lots of wasted spaces, take a look at a screenshot of my de box, the scroll bar is huge:

![diagram](https://cloud.githubusercontent.com/assets/1325611/5455966/6ad70580-8540-11e4-801e-ed2f62a167c8.png)