Make _expandContext_ @type: @id and set option values to be relative to the manifest location.

Fixes #369.

Author: gkellogg

tests/context.jsonld

@@ -23,7 +23,7 @@
     "compactArrays":        { "@type": "xsd:boolean" },
     "compactToRelative":    { "@type": "xsd:boolean" },
     "contentType":          { "@type": "xsd:boolean" },
-    "expandContext":        { "@type": "xsd:string" },
+    "expandContext":        { "@type": "@id" },
     "httpLink":             { "@type": "xsd:string", "@container": "@set" },
     "httpStatus":           { "@type": "xsd:integer" },
     "processingMode":       { "@type": "xsd:string" },

tests/expand-manifest.jsonld

@@ -550,7 +550,7 @@
       "name": "expandContext option",
       "purpose": "Use of the expandContext option to expand the input document",
       "option": {
-        "expandContext": "0077-context.jsonld"
+        "expandContext": "expand/0077-context.jsonld"
       },
       "input": "expand/0077-in.jsonld",
       "expect": "expand/0077-out.jsonld"

tests/toRdf-manifest.jsonld

@@ -1324,7 +1324,7 @@
       "name": "expandContext option",
       "purpose": "Use of the expandContext option to expand the input document",
       "option": {
-        "expandContext": "e077-context.jsonld"
+        "expandContext": "toRdf/e077-context.jsonld"
       },
       "input": "toRdf/e077-in.jsonld",
       "expect": "toRdf/e077-out.nq"