Subtitle Support?

[TheDerpySage]

I am working on Subtitle Support on the unicorn branch of my fork, and was wondering if it was something you were interested in.

I have some working logic in my fork that can either select the subtitle track from an mkv, or does its best to select a subtitle file in the same dir with the same root name as the video file, and applies them to the stream.

I would like to work more on the logic for the latter (scanning for and selecting external files) before applying it to master, but here are a few examples below