add .jshintrc file for in-repo addons

This addon adds a node .jshintrc file to the `/lib` folder so that in-repo addons are treated as being in node-land. Currently jshint uses the .jshintrc in the app's root, which is for the browser.

I used the same technique as for http-mocks/proxies: adding an intermediate blueprint called `lib` that creates `/lib/.jshintrc`, and installing that blueprint in the `beforeInstall` hook of the `in-repo-addon` blueprint.

The .jshintrc itself is pretty barebones, just indicating that it is a node environment. Let me know if you'd like me to add any other directives.