Condition will not work if annotated function is given

``` js
typeof this.config.condition === 'array'
```

[provider.js:222](https://github.com/aleross/angular-segment-analytics/blob/e10fb3bf74e46c8bfba604505625e5d870639c9f/src/provider.js#L222)

`typeof` never returns `"array"` :)

https://tc39.github.io/ecma262/#sec-typeof-operator
