Implement custom tooltips (tooltip role, in Google Charts) and formatters

[rarylson]

Use columns with role: 'tooltip' to set custom tooltips, like in the Google Charts API. Or use formatters.

Beautiful and good example of using tooltip roles: http://cmoreira.net/interactive-maps-generator/examples.html#07

And using formatters: https://developers.google.com/chart/interactive/docs/reference#formatters

See more: https://developers.google.com/chart/interactive/docs/customizing_tooltip_content#customizing-tooltip-content