Notify the list when the service is done

[EduFdezSoy]

Notify the new chapters list when the service finish scanning the folders.

I was thinking a shared preferences will do the job, we can change it to true when new chapters added and read it from the list activity eventually.

It may be some others ways to do that, Ill research it later.

[EduFdezSoy]

At this point the list is being updated when the scan is done 2821eb5