Release 2.3.17

Version 2.3.17 is a minor patch to registry-core which contains the following changes:

• Fix use of _format parameter so it (once again) works with command line tools like curl
• Add a new configuration option registry.useAbbrevXML which defaults to true to match existing deployments. Setting this to false results in less pretty XML rendering of RDF/XML payloads but avoids some performance overheads and lockups on pathological datasets. This setting does not affect RoR rendering.