Support for LDO's for hyper-schema draft-04

[samarism]

There seems to be no validation occurring on the "links" property in json hyper schemas. Under the "lib/json-schema/attributes/" folder there is no attribute for "links".

Its confusing because you can choose any of the HyperDraft1 ... HyperDraft4 as the default validator, but that validator never validates LDO's.