Adapt to these new window features upstream of mpv

[dyphire]

Move issues from https://github.com/mpvnet-player/mpv.net-experimental/issues/8

mpv has recently made a series of improvements to the Windows window and needs to be adapted in mpvnet. Ref https://github.com/mpv-player/mpv/pull/11469, https://github.com/mpv-player/mpv/pull/11473, https://github.com/mpv-player/mpv/pull/11494, https://github.com/mpv-player/mpv/pull/12196, https://github.com/mpv-player/mpv/pull/12452. In addition, there are some error fixes.