Update to elasticsearch 1.2.0

Closes #60.

(cherry picked from commit e55721a)
Throttle RabbitMQ connection in case of error

If you try to declare a queue with wrong settings (for example `durability`), the river creation fails but retry immediately after. It causes a lot of error messages in logs.

We can throttle that and give a delay of 10s before retrying again.

Also, we can add some informations about what is expected by the river as debug level information.

Closes #64.

(cherry picked from commit 3dd1d5b)
Exception when closing channel or connection

When we close the channel or connection for whatever reason (for example when retrying after a communication error), it throws an exception.

Actually, we need to test before closing that the resource is effectively opened.

Closes #65.

(cherry picked from commit 8ccf757)
Refactor integration tests

With this refactoring, it appears that some tests could fail when updating/deleting just indexed documents.

Another issue / commit will try to fix that.

Closes #63.

(cherry picked from commit ded1cff)
Update to RabbitMQ client 3.3.4

Closes #59.

(cherry picked from commit 5f86baf)
Provide documentation for running tests

Closes #56.

(cherry picked from commit a2f6961)