User can add images, and user has easy-access to create new posts, admin can easily distinguish admin features

- Added admin divs on pages with features accessible only to admins, offset with css, for clarity.
- Added easy-access blocks for creating new ads on posts index and locations index pages.
- Added javascript to build url from dropdown in the location/index page easy-access block
- Added image url field to posts table
- Added image and post body divs in posts show page
- Added css to style new divs in post show page
- Removed comments from gemfile
Removed the function from the model entirely, updated the controller. 

Coding Practices Question: I created a variable strictly for the purposes of readability (@found_results = @posts, in searches_controller.rb) - it serves no other purpose. Is that acceptable coding practice, or a bad idea?