"Jump to" menu rework

While trying to have the new UI style used for the menu "Jump to" I noticed that this menu is basically a mess so I decided to have a look. I tried a few things but I'm not sure what is best hence the PR so I can have more opinions.

Here are a few remarks about the menu:
- in file mode, this menu will list (if available) the chapters, the files currently in the playlist and the BD playlist
- in DVD mode, it will list the titles and chapters of the disk
- in DVB mode, it will list the available channels.
- the menu uses multiple columns in many case (for example to make a distinction between DVD titles and chapters), this style seems to be more or less deprecated since the new UI style isn't available in that case.

Basically it's a mess, many different things can be mixed together in the same menu and the multi-columns layout doesn't really look good...

What I did so far:
- use the new UI style and the more adapted radio bullet marks
- group items together in submenus to get more logical menus and to be able to drop the multi-columns layout (examples for [a file with chapters and some items in the playlist](http://i.imgur.com/wEhb8Wn.png) and [a DVD](http://i.imgur.com/2jkvXAm.png))
- fix a small bug I noticed while doing that.

However I'm not sure what we should do with that menu... I'm not sure it's a good idea to add another level of menu, we might menu to have for example two menus "Titles" and "Chapters" directly in the "Navigate" menu. Also I don't know what we want to keep in that menu exactly, for example the files in the playlist.