[TASK] Remove instead of add filter twice

lib/datadistributor.js

@@ -54,10 +54,21 @@ define(['filters/nodefilter'], function (NodeFilter) {
     }
 
     function addFilter(d) {
-      filters.push(d);
-      notifyObservers();
-      d.setRefresh(refresh);
-      refresh();
+      var newItem = true;
+
+      filters.forEach(function (f) {
+        if (f.getKey && f.getKey() === d.getKey()) {
+          removeFilter(f);
+          newItem = false;
+        }
+      });
+
+      if (newItem) {
+        filters.push(d);
+        notifyObservers();
+        d.setRefresh(refresh);
+        refresh();
+      }
     }
 
     function removeFilter(d) {

lib/filters/genericnode.js

@@ -49,10 +49,15 @@ define(['helper'], function (helper) {
       };
     }
 
+    function getKey() {
+      return value.concat(name);
+    }
+
     return {
       run: run,
       setRefresh: setRefresh,
-      render: render
+      render: render,
+      getKey: getKey
     };
   };
 });