Ergonomic API - convenience method to parse & run an app

[remkop]

Add convenience methods that parse command line arguments, and execute a Callable on success, or print a usage message to the console and exit on failure.

[remkop]

Duplicates #15.

[remkop]

// CommandLine
public static void run(<T extends Runnable> app, String ... args) {
    try {
        new CommandLine(app).parse(args);
    } catch (Exception ex) {
        System.err.println(ex.getMessage());
        CommandLine.usage(app, System.err);
        return;
    }
    args.run();
}