return json schema on OPTIONS request

This checks that the existing code base does the same thing as previously
over link headers. With this in place I can enable much more concise schema
data for collections. This does break the external API, but thats why you should
not develop against it yet.
make code more concise and explicit
fix

remember to always fix non broken stuff badly.
proper schema support for collections
Merge branch 'feature/support-options-verb' into develop