Resources lack event typedef

[MrBurmark]

It would be convenient if the resources had a typedef for their event type. I can use decltype but it seems unnecessarily complex. What do you think?

[trws]

That seems reasonable, I normally use auto so I suppose I didn't think about it. I'm beginning to think the entire resource setup might need some re-thinking as we do the RAJA cleanup for 1.0 as well.