refactor, cli, mocha tests

- add module pattern - works node.js and browser
- add .gitignore
- add mocha tests
- add cli support
- refactoring


### dateformat --help
```bash

  A node.js package for Steven Levithan's excellent dateFormat() function.

  Options
    --help          Show this help
    --version       Current version of package
    -d | --date     Date that want to format (Date object as Number or String)
    -m | --mask     Mask that will use to format the date
    -u | --utc      Convert local time to UTC time or use `UTC:` prefix in mask
    -g | --gmt      You can use `GMT:` prefix in mask

  Usage
    dateformat [date] [mask]
    dateformat "Nov 26 2014" "fullDate"
    dateformat 1416985417095 "dddd, mmmm dS, yyyy, h:MM:ss TT"
    dateformat 1315361943159 "W"
    dateformat "UTC:h:MM:ss TT Z"
    dateformat "longTime" true
    dateformat "longTime" false true
    dateformat "Jun 9 2007" "fullDate" true
    date +%s | dateformat
```