Feature/edit button on results

This feature adds Edit and Destroy buttons to the search results and detailed search results. Only authorized users can see the buttons. 
After the feature is implemented I suggest we modify nyucore.rb#index, which now lists all nyucores object without pagination. 
The following files were added:
﻿app/views/catalog/_document.html.erb
app/views/catalog/_show_default.html.erb
features/edit_button_on_results.feature
feature/step_definitions/edit_button_steps.rb
The following files were modified
app/controllers/nyucore_controller.rb
feature/step_definitions/record_steps.rb


@ekate [avoid trailing whitespace](https://github.com/bbatsov/ruby-style-guide#no-trailing-whitespace). Looks like there are 2 newlines here.