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/panel/vcpanel.js b/dev/js/src/panel/vcpanel.js
index 98a9b4b..e12c20c 100644
--- a/dev/js/src/panel/vcpanel.js
+++ b/dev/js/src/panel/vcpanel.js
@@ -43,10 +43,19 @@
       if (this.statView === undefined || !this.statView.shown()) {
         this.statView = corpStatVClass.create(this.vc, this);
         this.add(this.statView);
+        this.vc.oldvcQuery = KorAP.vc.toQuery();
       }
 
     },
     
+    /**
+     * Reload corpus statistic 
+     *
+     */
+    reloadCorpStat: function(){
+      this.statView.close();
+      this.addCorpStat();
+    }
     
   }
 });