User profile page story 64809366

[Pivotal tracker link](https://www.pivotaltracker.com/story/show/64809366)
- Added Scenarios to an existing cucumber feature `/features/users/user_list.feature` and some related steps
- Added links from list all users page to individual profile page
- Added View for profile page `views/users/show.html.erb` and spec `spec/views/users/show.html.erb_spec.rb`
- Styled the view into responsive bootstrap columns
- Added show method to users_controller with specs `spec/controllers/users_controller_spec.rb`
- Added helper for formatting nice dates to `helpers/users_helper.rb` and spec to `spec/helpers/users_helper_spec.rb`