Add Handlebars Layout possibility

This is basically #1075 without any partial support. If anyone wants to add this in, he or she is welcome to do so. I might do so myself some other day, but for now, this has to suffice. I hope this is alright as it is, and if anything should be changed before a merge, please tell me.

Oh, one more thing. You do not have to have your layouts reside in the `view/layouts` folder in this version. Anything within the view folder is possible.