Don't fail if 'options' is not defined in config

For my use, all the default options are suitable. However, if the `options` property is omitted from the config, twitch-irc fails to start. This is because [logger.js](https://github.com/Schmoopiie/twitch-irc/blob/master/logger.js#L34-L35) and [client.js](https://github.com/Schmoopiie/twitch-irc/blob/master/client.js#L164) were attempting to access properties of the `options` object without checking to see if it existed. I've defaulted `options` to an empty object if `options` is undefined, preventing the error.

This is a sloppy way of fixing this issue that will break if any code attempts to access a property of `options` that is two levels deep, i.e.
```javascript
var willError = config.options.this.errors || false;
```