Some themes not using .active-trail class

Hi, nice module and finaly something, what works!

Some themes are not using .active-trail class for primary menu. It would be good, to mention it in documentation.

For people with that themes (ie. Basic theme): just add same styling to .active-trail, as you have for .active or other name for active menu item.

For developer of this module: may be, it would be good, to have setting for active item class name in administration of module.