Fixed #4 - Disable rewrite option for all but internal redirect

lib/filterClasses.js

Index: lib/filterClasses.js
===================================================================
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -1055,21 +1055,20 @@
             collapse = !inverse;
             break;
           case "sitekey":
             if (!value)
               return new InvalidFilter(origText, "filter_unknown_option");
             sitekeys = value.toUpperCase();
             break;
           case "rewrite":
-            if (value == null)
-              return new InvalidFilter(origText, "filter_unknown_option");
+            if (!value.startsWith("abp-resource:"))
+              return new InvalidFilter(origText, "filter_invalid_rewrite");
             rewrite = value;
-            if (value.startsWith("abp-resource:"))
-              resourceName = value.substr("abp-resource:".length);
+            resourceName = value.substr("abp-resource:".length);
             break;
           default:
             return new InvalidFilter(origText, "filter_unknown_option");
         }
       }
     }
   }
 
@@ -1223,26 +1222,16 @@
    * @param {string} url the URL to rewrite
    * @return {string} the rewritten URL, or the original in case of failure
    */
   rewriteUrl(url)
   {
     if (this.resourceName)
       return resourceMap.get(this.resourceName) || url;
 
-    try
-    {
-      let rewrittenUrl = new URL(url.replace(this.regexp, this.rewrite), url);
-      if (rewrittenUrl.origin == new URL(url).origin)
-        return rewrittenUrl.href;
-    }
-    catch (e)
-    {
-    }
-
     return url;
   }
 });
 
 /**
  * Class for whitelist filters
  * @param {string} text see {@link Filter Filter()}
  * @param {string} regexpSource see {@link RegExpFilter RegExpFilter()}