message: Simplify default run logic
diff: @@ -842,20 +842,8 @@ fn get_compiler_by_backend(backend: Backend) -> Option<Box<dyn Compiler>> {
  }
  fn main() {
  - let options = {
  - let args: Vec<String> = env::args().into_iter().filter(|x| !x.starts_with("-")).collect();
  - match args.get(1).map_or("", |s| &s) {
  - // Default
  - "run" | "cache" | "validate" | "self_update" | "" => {
  - CLIOptions::from_args()
  - }
  - // Wasmer trying to run a file directly
  - _ => {
  - let run_options = Run::from_args();
  - CLIOptions::Run(run_options)
  - }
  - }
  - };
  + let options = StructOpt::from_iter_safe(env::args())
  + .unwrap_or_else(|_| CLIOptions::Run(Run::from_args()));
  match options {
  CLIOptions::Run(options) => run(options),
  #[cfg(not(target_os = "windows"))]
  