Add sorting options to media types

[da-anda]

currently you can't do much sorting, besides of desc/asc. It would be great it you could declare suiteable sort options for the various folder/media types and ofc fill the listitem with related infos to these sort modes as Kodi will show related sort info as label2.

[tadly]

Sorting has been added with 5c5d5a7 and will be in the next release.
Still missing the label2 thing which I'll have a look at sometime later