message: Apply mouse input in the input_test example
diff: @@ -5,12 +5,16 @@ use ggez::event::*;
  use ggez::graphics::{DrawMode, Point2};
  struct MainState {
  - pos_x: f32,
  + pos_x: i32,
  + mouse_down: bool,
  }
  impl MainState {
  fn new() -> MainState {
  - MainState { pos_x: 100.0 }
  + MainState {
  + pos_x: 100,
  + mouse_down: false,
  + }
  }
  }
  @@ -23,7 +27,7 @@ impl event::EventHandler for MainState {
  graphics::clear(ctx);
  graphics::circle(ctx,
  DrawMode::Fill,
  - Point2::new(self.pos_x, 380.0),
  + Point2::new(self.pos_x as f32, 380.0),
  100.0,
  1.0)?;
  graphics::present(ctx);
  @@ -35,10 +39,14 @@ impl event::EventHandler for MainState {
  button: MouseButton,
  x: i32,
  y: i32) {
  + self.mouse_down = true;
  + self.pos_x = x;
  println!("Mouse button pressed: {:?}, x: {}, y: {}", button, x, y);
  }
  fn mouse_button_up_event(&mut self, _ctx: &mut Context, button: MouseButton, x: i32, y: i32) {
  + self.mouse_down = false;
  + self.pos_x = x;
  println!("Mouse button released: {:?}, x: {}, y: {}", button, x, y);
  }
  @@ -49,6 +57,9 @@ impl event::EventHandler for MainState {
  y: i32,
  xrel: i32,
  yrel: i32) {
  + if self.mouse_down {
  + self.pos_x = x;
  + }
  println!("Mouse motion, x: {}, y: {}, relative x: {}, relative y: {}",
  x,
  y,
  