annotate Swagger JSON with OpenRiskNet (x-orn) annotation

[egonw]

As in:

{
    "swagger": "2.0",
    "info": {
        "version": "0.9.0",
        "title": "BridgeDb webservices",
        "x-orn-@id": "http://webservice.bridgedb.org",
        "x-orn-@type": "x-orn:Service"
    },
    "consumes":["text/html"],
    "produces":["*/*"],
    "host": "webservice.bridgedb.org",
    "schemes": [
        "http",
        "https"
    ],
    "paths": {
        "/{organism}/xrefs/{systemCode}/{identifier}": {
            "get": {
                "x-orn-@type": "x-orn:Identifier",
                "x-orn:path": "http://webservice.bridgedb.org/{organism}/xrefs/{systemCode}/{identifier}",
                "x-orn:method": "Post",
                "description": "Returns a list of xrefs that map to a given identifier, data source, and organism.",
		        "tags":["Genes"],