Add native MediaPlayer

[TimGels]

As of now the LibVLC(Sharp) implementation in UWP contains a couple of issues like #7, #24 and some smaller ones that i don't see getting fixed anytime soon.

We could for example add the native MediaPlayer player from Windows 10 and give the user the ability to switch player types in a settings page (#25).

[TimGels]

This will most likely not be needed anymore as #7 is fixed. Needs review at a later stage.