Bookplayer: Inconsistent time format in Player and chapters overview

[pichfl]

The total time omits hours in the chapters list for some reason. Both views should use the same kind of NSDateFormatter

Reported by @boettges here:
https://github.com/TortugaPower/BookPlayer/issues/231#issuecomment-418788055

[GianniCarlo]

reference: https://forums.developer.apple.com/thread/32475

Seems like we'll have to keep the nowPlaying dictionary ourselves and set it entirely in MPNowPlayingInfoCenter instead of just updating one value at a time

[pichfl]

Looking at the original comment by @boettges again I realized that there is something off about this. Shouldn't we treat books with a single chapter like if they have no chapter at all? @GianniCarlo I think the work you did for #231 makes this easy to handle.

[pichfl]

Extracted the single chapter issue into #242

[boettges]

Just updated the app and I’m impressed. You came up with a very clean solution 👌
Thank you for taking the time.

[pichfl]

@boettges thanks, but I guess your reply was meant for #231 - This ticket is for the other issue you reported regarding the formatting of the duration.