macosx.m: fix resizing from display

The display is currently using vout_window_ReportSize and should be updated to avoid that.

I've written the work for 3.0 and forward-ported to 4.0 but I'm also checking against caopengllayer on 4.0, in particular because the resizing is much much less smooth than in 3.0 and I want to be sure it's coming from the video output core code and not the display code.