Move INTERNET permission to proper placement
Use non-standard clients for Picasso and Retrofit

In creating this demo, I encountered issues handling caching
and image fetching. I needed to switch to different types of
HTTP clients to work around it. An interesting topic for investigation
here.
Make sure to tell Github API what version we are expecting
Add basic UserDetailActivity
Pass a callback to Adapter allowing item clicks to launch mock detail
Pass user name to user detail activity