Support browsing movie sets

[Robert Meijers]

Currently you can only browse movies. While Kodi supports movie sets, for which it groups all movies of a series under a single name. Like Iron Man, Iron Man 2 and Iron Man 3 would be shown as one (Iron Man). Upon selecting it would then show all movies in the set. This makes browsing the movies a bit easier.

There are a couple of ways to implement this, but I think there are two ways which I would be the easiest for the user.
The first is to add a Movie sets item to the Videos menu item, so it would become:

• Movies
• Movie sets
• TV Shows
• Music videos
• Recently added

The second is to add a new setting: Show movies in sets. This would then change the behavior of the Movies item to display the sets.

I don't think adding a sub menu to Movies (to select either Movies or Sets or something alike) is a desirable option, as it adds one more sub menu.