Change dublincore property to dublinCore

[monotasker]

We have used camel case for property names except for the dublincore property of the response document schema at the Collections endpoint. This property should be renamed dublinCore to conform to a consistent capitalization of property names.

[PonteIneptique]

As a wise man said one day:

[monotasker]

I just noticed that "dublincore" needs to be changed in the context document too.

[PonteIneptique]

Fixed by #230