Added on reply/request/connect functions. 

* Also fixed some defaults arguments.
* Also added some support for functionality recently added to bosh/tcp e.g. not crashing on bad parse and "timeouts" Needs more work though

Problems:
Lots of {ok, _} = which will cause crashes
Not sure when on_error is called, if it is going to return failed requests for example. timeouts etc
Why change the resource? If these are bugfixes, should go in an independent commit. And pushed as such to esl/escalus.