Make multiple argument lists useful

[szeiger]

The only situation where you really need multiple argument lists is for path-dependent argument types but this breaks Twirl's translation scheme because argument lists have to merged to implement play.twirl.api.TemplateX. An obvious fix would be not to extend a TemplateX class or generate a render method when multiple argument lists are used.

[wsargent]

@szeiger can you provide an example?