Remove code-literal wrapping of "link" objects
Remove code-literal wrapping of "link" objects

Per @dgeb's [comment][c], these objects won't appear in the JSON under a
literal `"link"` key, so they shouldn't written as such.

[c]: https://github.com/json-api/json-api/pull/187#issuecomment-33905900

benoittgt/json-api,beauby/json-api,eneuhauser/json-api,equivalent/json-api,dongguangming/json-api,dieface/json-api,greyhwndz/json-api,dieface/json-api,kjwierenga/json-api,RavelLaw/json-api,jerel/json-api,nonsensery/json-api,Volcanoscar/json-api,wvteijlingen/json-api,greyhwndz/json-api,nonsensery/json-api,erickt/json-api,csantero/json-api,redaktor/json-api,jamesdixon/json-api,json-api/json-api,jerel/json-api,jamesdixon/json-api,csantero/json-api,jede/json-api,eneuhauser/json-api,janusnic/json-api-1,cesarmarinhorj/json-api,kjwierenga/json-api,benoittgt/json-api,dongguangming/json-api,ashleygwilliams/json-api,janusnic/json-api-1,redaktor/json-api,dieface/json-api,greyhwndz/json-api,RavelLaw/json-api,jerel/json-api,eneuhauser/json-api,erickt/json-api,janusnic/json-api-1,sloria/json-api,wvteijlingen/json-api,json-api/json-api,ashleygwilliams/json-api,redaktor/json-api,json-api/json-api,jede/json-api,bf4/json-api,csantero/json-api,bf4/json-api,beauby/json-api,erickt/json-api,jamesdixon/json-api,cesarmarinhorj/json-api,json-api/json-api,Volcanoscar/json-api,RavelLaw/json-api,Volcanoscar/json-api,ashleygwilliams/json-api,wvteijlingen/json-api,sloria/json-api,json-api/json-api,benoittgt/json-api,bf4/json-api,beauby/json-api,RavelLaw/json-api,RavelLaw/json-api,equivalent/json-api,nonsensery/json-api,sloria/json-api,dongguangming/json-api,kjwierenga/json-api,cesarmarinhorj/json-api,jede/json-api,equivalent/json-api