Add retry mechanism in case of episodes list retrieve failure instead of just failing.

If it can't after a couple of retry (5 by default, can be changed on the command line) it will just ignore it and go to the next anime.

src/interface/IConfigTask.d.ts

@@ -1,4 +1,5 @@
 interface IConfigTask {
   address: string;
   config: IConfigLine;
+  retry: number;
 }