This plugin adds options for setting rounded corners on bar and column charts.
The contents of the plugin is located in the javascript file
rounded-corners.js.
This plugin is published under the MIT license, and the license document is included in the repository.
The plugin adds four options to the column series object; borderRadiusTopLeft,
borderRadiusTopRight, borderRadiusBottomLeft and borderRadiusBottomRight.
If the options are given as numbers, they are interpreted as pixels. If given
as percentage strings, they are percentages of the column width.