[CLOUDSRV-4455] Fixed HTTP calls that return 4xx and 5xx errors to prope...

[CLOUDSRV-4455] Fixed HTTP calls that return 4xx and 5xx errors to properly return an error.

[CLOUDSRV-4473] Updated the API to be more Node-like. Now you can create ACSApp instances yourself and not need to immeidately call a creator function.

[CLOUDSRV-4474] Changed the code so that you don't have to manually deal with session cookies. Once you login with your ACSApp instance, it is logged in for all calls until you logout. You can still manipulate the myacsApp.sessionCookieString variable, but it is not advised.
We can set cookie string by default, but we should provide a way for users when they don't want to set cookie automatically. We can use an application level options like:
```
var ACSNode = require('acs-node'),
	acsApp = new ACSNode(acsKey, {
		apiEntryPoint: acsEntryPoint,
		autoSetCookieString: false,
		prettyJson: true
	});
```