Helper functions on each `Model` would be nice

[mirrorcult]

Currently they're all just pure data but for certain things (like getting the 'default' variable value easily, or getting the international name for something)

I don't like what the LiveSplit-created API does where it loads expected 'useful' values like the world record by default into certain things like the category models. Basically 'helpers' that involve doing other API calls should probably be avoided just for consistency's sake, and they definitely shouldnt be getter properties (as I think this makes people severely underestimate how long these can take)