Sorting could use some improvements

[FunctionalHacker]

I don't know if this is a limitation of the YLE API but right now because of the sorting of episodes, this plugin is basically unusable for watching any series with more than a couple episodes.

Steps to reproduce:

1. Do a series search for "itse valtiaat"
2. Try to find episode 1 of the series
3. You will notice that the episodes are not sorted by episode number, but alphabetically

[hirsivaja]

I agree, the current implementation is not very good. Partly because of limitations in the API, but still...

Seems like Vesa Toivonen has already implemented this:
vesatoivonen@20b561a

@vesatoivonen Pull request would be appreciated

[vesatoivonen]

My current implementation is bad and i'm planning to fix that once kodi19 is released with it's transition to python3.
Can do a PR after that's done.