For a mediator responses we should check if the content type contains the correct string rather than exactly equals it

[rcrichton]

Sometimes ; charset=utf-8 or more options could be appended to the content-type.

See https://github.com/jembi/openhim-mediator-file-queue/blob/master/lib/worker.js#L76

[bausmeier]

There is already a dependency on the type-is module so that can be used.

[rcrichton]

Cool good idea.