add testFeedExists script; remove redundant uniqueId functions; add CFBundleURLTypes info.plist key

Evergreen/Scriptability/Author+Scriptability.swift

@@ -38,6 +38,7 @@ class ScriptableAuthor: NSObject, UniqueIdScriptingObject {
     // I am not sure if account should prefer to be specified by name or by ID
     // but in either case it seems like the accountID would be used as the keydata, so I chose ID
 
+    @objc(uniqueId)
     var scriptingUniqueId:Any {
         return author.authorID
     }
@@ -49,11 +50,6 @@ class ScriptableAuthor: NSObject, UniqueIdScriptingObject {
         return self.author.url ?? ""
     }
     
-    @objc(uniqueId)
-    var uniqueId:String  {
-        return self.author.authorID
-    }
-    
     @objc(name)
     var name:String  {
         return self.author.name ?? ""