Implemented VC caching & deserialization with string[] and cache option.

Change-Id: I42a7d4211d903587254d6b7fc2d6c242e55a2032
diff --git a/src/test/resources/collection/query-with-vc-ref.jsonld b/src/test/resources/collection/query-with-vc-ref.jsonld
new file mode 100644
index 0000000..d50cd2a
--- /dev/null
+++ b/src/test/resources/collection/query-with-vc-ref.jsonld
@@ -0,0 +1,15 @@
+{"query":{
+    "@type":"koral:token",
+    "wrap":{
+      "@type":"koral:term",
+      "layer":"orth",
+      "key":"der",
+      "match":"match:eq",
+      "foundry":"opennlp"
+    }
+  },
+  "collection": {
+    "@type": "koral:docGroupRef",
+    "ref": "cache-goe"
+  }
+}