Bar chartview, set barwidth to 1.0, but still have spacing between bars

## What did you do?


I created a bar chart view, and show it successful

## What did you expect to happen?

I would like to make bar width equal to 1.0, set 4 different colors for 4 values, and remove spacing between bars

## What happened instead?

There is a small line between two bars, which is not the effect I expect, how to remove the small line between two bars

## Charts Environment

**Charts version/Branch/Commit Number:3.2.1
**Xcode version:10.0
**Swift version:4.2