Remove arbitrary sleep

[expectocode]

Once get_window_at_point can take an ignore_window parameter, as #22 adds, we could get the window geometry of the window below the cursor before destroying our own geometry and we could remove the arbitrary 40ms sleep after our unmapping (which was for waiting for our own window to disappear, I think).

[Lonami]

For the record, we're talking about this one:

hacksaw/src/main.rs

Line 234 in 3faf56c

std::thread::sleep(std::time::Duration::from_millis(40));

I presume we still want to keep this one, although it could use a comment:

hacksaw/src/lib/mod.rs

Lines 132 to 136 in 0845862

	if reply.status() as u32 == xcb::GRAB_STATUS_SUCCESS {
	return true;
	} else if i < CURSOR_GRAB_TRIES - 1 {
	std::thread::sleep(std::time::Duration::from_millis(100));
	}

[expectocode]

yes indeed