Test keyword aliasing when @vocab is used

This addresses #186.

Author: lanthaler

test-suite/tests/compact-0028-context.jsonld

@@ -0,0 +1,9 @@
+{
+  "@context": {
+    "@vocab": "http://xmlns.com/foaf/0.1/",
+    "homepage": {
+      "@type": "@id"
+    },
+    "uri": "@id"
+  }
+}

test-suite/tests/compact-0028-in.jsonld

@@ -0,0 +1,12 @@
+{
+  "@context": {
+    "@vocab": "http://xmlns.com/foaf/0.1/",
+    "homepage": {
+      "@type": "@id"
+    },
+    "uri": "@id"
+  },
+  "uri": "http://me.markus-lanthaler.com/",
+  "name": "Markus Lanthaler",
+  "homepage": "http://www.markus-lanthaler.com/"
+}

test-suite/tests/compact-0028-out.jsonld

@@ -0,0 +1,12 @@
+{
+  "@context": {
+    "@vocab": "http://xmlns.com/foaf/0.1/",
+    "homepage": {
+      "@type": "@id"
+    },
+    "uri": "@id"
+  },
+  "uri": "http://me.markus-lanthaler.com/",
+  "name": "Markus Lanthaler",
+  "homepage": "http://www.markus-lanthaler.com/"
+}

test-suite/tests/compact-manifest.jsonld

@@ -168,5 +168,11 @@
     "input": "compact-0027-in.jsonld",
     "context": "compact-0027-context.jsonld",
     "expect": "compact-0027-out.jsonld"
+  }, {
+    "@type": ["test:TestCase", "jld:CompactTest"],
+    "name": "Alias keywords and use @vocab",
+    "input": "compact-0028-in.jsonld",
+    "context": "compact-0028-context.jsonld",
+    "expect": "compact-0028-out.jsonld"
   }]
 }