Add errorHandler to connect arguments

[chiaolun]

Attach an error handler before connecting, otherwise errors from the connection could be emitted before a handler is attached, causing node process to exit.

[aricart]

@chiaolun the connection is resolved or rejected in a promise, so the event handler is not needed in the initial connection, and the reason why you cannot install it until the connection resolves.

[chiaolun]

The specific error that was crashing our server before the error handler could be attached was an "Authentication Timeout" coming from the Socket, which was thrown from processInbound right here:
https://github.com/nats-io/nats.ts/blob/v1.2.4/src/protocolhandler.ts#L642

It isn't thrown from the connect function, it goes into the client EventEmitter.

trace (v1.2.4):

    at ts-nats.lib:protocolhandler.Object.handlers.data (app:///node_modules/ts-nats/lib/protocolhandler.js:445:18)
    at ts-nats.lib:protocolhandler.ProtocolHandler.processInbound (app:///node_modules/ts-nats/lib/protocolhandler.js:580:34)
    at ts-nats.lib:protocolhandler.ProtocolHandler.processErr (app:///node_modules/ts-nats/lib/protocolhandler.js:905:35)
    at ts-nats.lib:protocolhandler.Function.toError (app:///node_modules/ts-nats/lib/protocolhandler.js:894:20)```

[aricart]

@chiaolun OK, that makes sense - the fix will need to be different than what you are proposing here. I have opened #95.

[chiaolun]

Thank you!