Added EventListener for graying corpus statistic(plus renaming)

Change-Id: I41da48f92a9f5abccb6a64a9a4f2c1192e713327
(cherry picked from commit b990f6ad18afb79e10e4c88b505e4429aeaa07e2)
diff --git a/dev/js/src/vc/doc.js b/dev/js/src/vc/doc.js
index 2a0e872..132c4a8 100644
--- a/dev/js/src/vc/doc.js
+++ b/dev/js/src/vc/doc.js
@@ -150,7 +150,10 @@
       };
       
       if(KorAP.vc){
-        KorAP.vc.checkGrayingStat();
+      //Replaced through Event
+      //KorAP.vc.checkGrayingStat(this); 
+      var vcchevent = new CustomEvent('vcChange', {'detail':this});
+      document.dispatchEvent(vcchevent);
       }
       
       return e;