Allow passing username and password to .connect() in JS client

First off, apologies to not updating the test suite. I could not figure out how it all ties together.

Stomp.Client#connect does not accept more parameters than one without raising an error on connect. It all works fine, but if supplying more than one parameter to connect, the onConnected callback won’t be called.

Additionally I fixed a typo for the errorCallback in the HTTP transport.

I also added support for the errorCallback, which allows users to suppress the logging message sent on error.