Add an option for allowing pointer events to pass through the mpv
window. This could be useful in cases where a user wants to display
transparent images/video with mpv and interact with applications beneath
the window. This commit implements this functionality for x11 and
wayland. Note that whether or not this actually works likely depends on
your window manager and/or compositor. E.g. sway ignores pointer events
but the entire window becomes draggable when you float it (nothing under
the mpv window receives events). Weston behaves as expected however so
that is a compositor bug. Excuse the couple of completely unrelated
style fixes (both were originally done by me).
dbc0fcea1b