Samples: Dispose resources in the F# sample

samples/LibVLCSharp.FSharp.Sample/Program.fs

@@ -3,10 +3,13 @@ open LibVLCSharp
 
 [<EntryPoint>]
 let main argv =
-    printfn "Hello World from F#!"
     Core.Initialize()
     let libVLC = new LibVLC()
     let mp = new MediaPlayer(libVLC)
-    mp.Play(new Media(libVLC, new Uri("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"))) |> ignore
-    let result = Console.ReadKey()
+    let media = new Media(libVLC, new Uri("http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"))
+    mp.Play(media) |> ignore
+    media.Dispose()
+    Console.ReadKey() |> ignore
+    mp.Dispose()
+    libVLC.Dispose()
     0