Update LinkedIn API to fetch email

This is a pretty straight forward change. Noticed that we aren't pulling or saving email addresses from LinkedIn. Their earlier versions of the API didn't allow you to get the email, but they later launched different scopes that you can default in your app configuration. 

This requires the scope r_emailaddress. I've added that as the default scope, as in 99% of cases you will want it. However, feel free to just cherry pick the server example updates if you don't want to mess with defaults.