Change the subEvent from a MASTER_REQUEST to a SUB_REQUEST

Hey,

Since PR #11 my tests are failing on my API. The reason is that my API needs a token on each request, and it was not necessary to add them in the `links`. However in #11 it makes a MASTER_REQUEST sub call which of course triggers my token listener.

I changed it to a SUB_REQUEST, and all tests are still passing.

Question ... Is it really necessary that the subEvent is called with a MASTER_REQUEST?