SteamApi.getFriendList throws error when User has friend privacy set to private

[Emosewaj]

Expected behaviour: A proper error is thrown using the callback, or 0.
Actual behaviour: Cannot read property 'friends' of undefined @ getFriendsList.js:16

How to reproduce:

1. Set profile's Friends List privacy to Private
2. Attempt to run SteamApi.getFriendList(<ID>, <KEY>, <cb>);