Re #367 - Make lightbox detect and respond to URL fragments

• rcarousel.js
  - cleaned-up spacing
  - removed outdated comments
  - added goToIndex method
  - refactored setCurrentItemIndex
  - jslinted the code

• EuEdmObjectPage.js
  - added hideLightboxContent method

• contributions-show.js
  - refactored the way the carousel adds and updates content. instead of making
    an http request it now relies on data attributes within the <a> tag of
    item-placeholder <li>’s

• attachments_controller.rb, contributions_controller.rb
  - altered the max items per page to 1,000. this needs to be refactored so that
    there is no longer a limit on the items served

• _display-images.html.erb
  - refactored to match new implementation in contributions-show.js
  - added comments that explain the different html elements more thoroughly