Release v2.1.0

• Added support for _classes on each tabs item

Release v2.0.4

Fixes an issue where the alt attribute of the tab image was missing quotes

Release v2.0.3

• make title optional (#8)
• add a visited class when tabs have been clicked, for consistency with other adapt presentation components
• minor code cleanup

Release v2.0.2

updates for better compatibility with the Adapt Authoring Tool, fix for #6