add .jshintrc files to addon blueprint

I felt that it would be helpful to have these already in place when making an addon. Since root is node-land I had to put a node .jshintrc in the root and override it with browser ones in app and addon.

I'm not sure if I did something bad with that change in `blueprints/addon/index.js`, but I needed it to ensure that the .jshintrc gets put in app.
doesn't this already come from the app blueprint?

cc @rwjblue