Use cli-table instead

[cli-table](https://github.com/LearnBoost/cli-table) is a good Node module that can help us here. We only push the table rows and cli-table will generate the ascii table.

Cli-table also offers many features that we can use later:

 - Customizable characters that constitute the table.
 - Color/background styling in the header through colors.js
 - Column width customization
 - Text truncation based on predefined widths
 - Text alignment (left, right, center)
 - Padding (left, right)
 - Easy-to-use API

I published this version of plugin as npm package: `git-issues1`.

     # uninstall git-issues
     sudo npm uninstall git-issues -g
     # install git-issues1
     sudo npm install git-issues1 -g

Please test it before merge!