It would be useful to have an example Custom Tag/Custom Style configuration that:

• is tailored for specific versions (2.5, 3.0)
• is version controlled.

Goal of this task:

• add an example Custom Tag/Custom Style configuration to BehatBundle (the definition and required files). Make a new suite richtext/feature file that adds it to the product.

Idea: run it as setup step for the fourth job in BehatBundle? https://github.com/ezsystems/BehatBundle/blob/7.0/.travis.yml#L32
So we would know if something breaks