Dropping Window doesn't close it (X11)

[gmorenz]

For example, I would expect the following code to close the window immediately, instead of closing it when you kill the process

extern crate glutin;

fn main() {
    glutin::Window::new();
    loop {}
}

Adding (self.display.xlib.XSync)(self.display.display, 0); to the end of XWindow::drop fixes the issue, I'm not familiar enough with X to say if it's the right way to fix the issue.

[tomaka]

Closing for rust-windowing/winit#79