RequestBuilder now generates relative url. Absolute url is created in HttpClient.
Added follow method to Link entity class.
Added Id entity microtype.
Implemented lazy proxy behavior for links.
Changed ResultPage#next to use Link instead of callback.
Implemented next Link parsing in KOSapiResponse.
Implemented next Link creation on ResultPage.
Prepended Link attributes with link_ prefix to avoid attribute clashes with KOSapi entities.