Cross-reference API calls

[jakobyc]

I.e., cross-reference a received item Id with another call and return the results.

[jakobyc]

I'm thinking of changing all calls that return an array of IDs to return an array of objects that contains the ID and a property for Information about the ID (probably a generic). I.e., GetAchievements() would be able to drill in on each achievement specifically so we could do something like client.Achievements.GetAchievements().Where(x => x.Id == "5").AchievementInfo rather than getting our achievement IDs and then separately calling client.Achievements.GetAchievement("achievementid");