Ignore errors from env_logger init.

[EnigmaCurry]

I want to use just as a rust library from my existing rust application, which already uses env_logger:

use env_logger::Env;

fn main() {
    env_logger::init_from_env(
        Env::default()
            .filter_or("LOG_LEVEL", "warn")
            .write_style_or("LOG_STYLE", "always"),
    );
    set_env_default("DATABASE_URL");

    // This fails with env_logger double initialization error:
    if let Err(code) = just::run() {
        std::process::exit(code);
    }
}

If I run just::run() after I have already initialized env_logger, I get this error:

Builder::init should not be called after logger initialized: SetLoggerError(())
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

It looks like the correct fix is to use env_logger's try_init instead, and so that's what I've done, which fixes the above code to have no more errors.

[casey]

Seems reasonable to me!

[casey]

Also, although just isn't really designed to be used as a library, I'm not opposed to doing simple things to make using it as a library easier, like making run() take command line arguments, so they can be passed from a source other than the binary's command line arguments.