message: Return Result from main
diff: +extern crate failure;
  extern crate pikelet;
  extern crate structopt;
  +use failure::Error;
  use pikelet::cli::Opts;
  -use std::process;
  use structopt::StructOpt;
  -const EXIT_OK: i32 = 0;
  -
  -#[cfg(os = "windows")]
  -const EXIT_ERR: i32 = 0x0100;
  -#[cfg(not(os = "windows"))]
  -const EXIT_ERR: i32 = 1;
  -
  -fn main() {
  - process::exit(match pikelet::cli::run(Opts::from_args()) {
  - Ok(()) => EXIT_OK,
  - Err(err) => {
  - eprintln!("{}", err);
  - EXIT_ERR
  - },
  - })
  +fn main() -> Result<(), Error> {
  + pikelet::cli::run(Opts::from_args())
  }
  