Make link clickable in minecraft

[rom1504]

from @demipixel

Convert Hello there! Here is a [link](http://www.google.com) in **bold**
to

{
  text: '',
  extra: [
    {
      text: 'Hello there! Here is a '
    },
    {
      text: 'link',
      color: 'blue',
      hoverEvent: {
        action: 'show_text',
        value: 'http://www.google.com'
      },
      clickEvent: {
        action: 'open_url',
        value: 'http://www.google.com'
      }
    },
    {
      text: ' in '
    },
    {
      text: 'bold',
      bold: true
    }
  ]
}