Tooltip with StackedBar not being rendered

## Expected Behavior
When I add a Tooltip for a StackedBar, I expect the tooltip being rendered along with the chart. This is also happening to me on Bar charts.

## Current Behavior
The tooltip is not being rendered. I created a small pen to show you the behavior. I started from a similar pen which worked for Line charts.

The chart is being rendered, but the tooltip is not being rendered.

## Possible Solution
Not sure, if it's not implemented yet or if it should be rendered but I'm missing something. I thought that the tooltip worked since on the documentation there's this mention:

> The tooltip component is a great companion to the line, stacked area, stacked bar and grouped bar charts.

## Steps to Reproduce (for bugs)
Please, check this pen: https://codepen.io/juanpaucar/pen/maJrgQ

## Screenshots (if appropriate):

## Context
I just started using this charts and it seemed weird to me that they don't work for Bar and Stacked Bar.

## Your Environment
Ubuntu 18.04
Node 10.13.0
Britecharts and Britecharts-react latests versions
https://codepen.io/juanpaucar/pen/maJrgQ