Allow blocking/synchronous delivery to consumers

[patrikwlund]

It simplifies some testing scenarios because you don't need infrastructure and boilerplate for message waits.

Note that this does nothing regarding the ack/nack flow, it just allows us to make the initial publish/delivery operation blocking.

[odalet]

Hi, once a gain a cool addition. I modified a bit your code with mostly cosmetic changes (well renamed a few things too).
I also made the new property of RabbitServer read-only (and hence, defined from the constructor). I feel it's a bit cleaner as once set, this should not change later.

Nuget coming soon

[patrikwlund]

I modified a bit your code

Looks good, thanks!