Allowing main breadcrumb color setting to work in nav and ul containers.

Sort of fixes zurb/foundation#4801

Link color setting variable can now be applied to both `nav` and `ul` markup scenarios. I have removed the extra `text-transform` property as it should bubble up properly.  Text underline on hover will likely not be possible with a `nav > a` xpath because the `:before` content is a child of the link and underlines on hover as well.