Support layouts defined in libraries

[drewhamilton]

Layouts defined in libraries are not final, so they can't be used in annotations:

There are a few ways to support non-final layout resources off the top of my head:

• Generate final versions of layout resources (I think Butter Knife does this, not sure how it works)
• Support setting layout at runtime by generating a set...ViewHolderLayout method for each @ViewHolder with an undefined layout