Make Native Bookmarks work

Here's a fix to make native bookmarks work. I tested custom and native for episodes and they both work now. I haven't tested them with movies yet but they should be fixed too.

One persistent problem that I haven't quite figured out yet is that when re-resuming a previously resumed episode the new bookmark doesn't get saved and totalTime is 0 in onPlaybackStarted. That problem already existed in the old code but I haven't figured out what's causing it yet.