CLI help and version flags

[SheetJSDev]

$ marky-markdown -h
/usr/local/lib/node_modules/marky-markdown/bin/marky-markdown.js:14
  if (err) throw err
           ^

Error: ENOENT: no such file or directory, open '/private/tmp/-h'

There's a help message that only shows up with no arguments:

$ marky-markdown 
Usage:

marky-markdown some.md > some.html

I'd suggest supporting a few flags:

• -h or --help to display the help message (maybe it can be collapsed to one line like Usage: marky-markdown some.md > some.html)
• -V or --version to display the version number (which would be available from the bin script as require('../marky.json').version)

[revin]

Good ideas. I find myself wanting better CLI options all the time, personally.