Macro rgb16

macro_rules! rgb16 {
    ($r:expr, $g:expr, $b:expr) => { ... };
}

As per rgba16, but automatically selects alpha=true.

#[macro_use]
extern crate retro_pixel;

fn main() {
  assert_eq!(rgb16!(31, 0, 0), rgba16!(31, 0, 0, true));
  assert_eq!(rgb16!(0, 31, 0), rgba16!(0, 31, 0, true));
  assert_eq!(rgb16!(0, 0, 31), rgba16!(0, 0, 31, true));
}