cocoa_common: implement mouse movement notifications

Notify the core of mouse movement events. The coordinates are converted to a
coordinate system with the origin in upper left corner, since Cocoa has it in
the lower left corner.

video/out/cocoa_common.m

@@ -829,6 +829,16 @@ int vo_cocoa_cgl_color_size(struct vo *vo)
 {
     if (self.videoOutput->opts->fs)
         vo_cocoa_display_cursor(self.videoOutput, 1);
+
+    NSView *view = self.contentView;
+    NSPoint loc = [view convertPoint:[theEvent locationInWindow] fromView:nil];
+    NSRect bounds = [view bounds];
+
+    int x = loc.x;
+    int y = - loc.y + bounds.size.height; // convert to x11-like coord system
+    if (CGRectContainsPoint(bounds, NSMakePoint(x, y))) {
+        vo_mouse_movement(self.videoOutput, x, y);
+    }
 }
 
 - (void)mouseDragged:(NSEvent *)theEvent