v1.12.0

1. extra arguments support (special arguments after --, from #22)
2. terminal width detect only before help info generation
3. document update

Extra special arguments support has an example extra-arguments
Terminal width detection invokes a system call stty, only when you need to generate the help info FormatHelp. Which improves the runtime efficient for normal cases (when you don't need to show the help info).

Full Changelog: v1.11.0...v1.12.0