added utilities for sending Bson objects as vert.x JsonObjects over the event bus

As a partial solution to this issue I created a Util class that allows for sending MongoDB Bson Objects as vert.x JsonObjects
https://github.com/vert-x/mod-mongo-persistor/issues/53

I based it on patrickvankann's snippets found in this issue
https://github.com/vert-x/mod-mongo-persistor/issues/35

let me know your thoughts on this change. 

As far as vert.x goes we should potentially consider adding better BSon support into JsonObject or allow for different implementations. You can't even put a java Date object into a JsonObject at all currently and it should really be considered a core type in my opinion.
What does the caller do with this exception?