graying corpus statistic(plus tests+vc test fixed) and fix vc serialization

Change-Id: I3f934c2cc0ebbb0a91b5fa8f529bf3f5c3ebd391
(cherry picked from commit 172d6a4bbc7d29a0fe7c23b114fbbf485e2f4aeb)
diff --git a/dev/js/src/vc/docgroupref.js b/dev/js/src/vc/docgroupref.js
index 7d3ecea..fa82a4b 100644
--- a/dev/js/src/vc/docgroupref.js
+++ b/dev/js/src/vc/docgroupref.js
@@ -109,7 +109,7 @@
         // Append new operators
         e.appendChild(op.element());
       };  
-
+      KorAP.vc.checkGrayingStat();
       return this.element();
     },
 
@@ -207,7 +207,6 @@
       return this;
     },
 
-
     /**
      * Click on the unspecified object
      */
@@ -261,9 +260,13 @@
       };
     },
 
+
+    incomplete : function () {
+      return this.ref() ? false : true
+    },
     
     toQuery : function () {
-      if (!this.ref())
+      if (this.incomplete())
         return "";
 
       // Build doc string based on key