js/clone.js: .csv export, add productivity info

See #2327.

browser/js/clone.js

@@ -1205,6 +1205,7 @@ Clone.prototype = {
             "cluster", "name", "id",
             "system", "tag",
             "v", "d", "j",
+            "productivity",
             "sequence"
         ]
 
@@ -1220,6 +1221,7 @@ Clone.prototype = {
             this.getCluster().join("+"), this.getName(), this.id,
             this.get('germline'), this.getTagName(),
             this.getGene("5"), this.getGene("4"), this.getGene("3"),
+            this.getProductivityName(),
             this.getSequence()
         ]