message: Update graphics_settings example
  `NumSamples::try_from` was changed from a u32 to a u8, so the example
  needs to be updated accordingly.
diff: //! resize windows, etc.
  //!
  //! Prints instructions to the console.
  +use std::convert::TryFrom;
  use ggez::conf;
  use ggez::event::{self, KeyCode, KeyMods};
  @@ -192,7 +193,7 @@ fn print_help() {
  struct Opt {
  /// what level of MSAA to try to use (1, 2, 4, 8)
  #[argh(option, short = 'm', long = "msaa", default = "1")]
  - msaa: u32,
  + msaa: u8,
  /// try to use OpenGL ES 3.0 instead of regular OpenGL.
  #[argh(switch, long = "es")]
  es: bool,
  @@ -222,7 +223,7 @@ pub fn main() -> GameResult {
  )
  .window_setup(
  conf::WindowSetup::default().samples(
  - conf::NumSamples::from_u32(opt.msaa)
  + conf::NumSamples::try_from(opt.msaa)
  .expect("Option msaa needs to be 1, 2, 4, 8 or 16!"),
  ),
  )
  