Resource request options

Add the ability to use an object of request options rather than just a url when specifying resources. This allows developers to specify API keys in headers, and sets the stage for defining resource parameters in a more centralized location.

```html
...
    "resources": {
        "doges": {
            "url": "https://example.com/api/v2/resources/4521zb/such-doges",
            "headers": {
                "key": "123"
            },
            "auth": "user:pass"
        }
	}
...
```