message: Added brief explanation of fullscreen usage.
diff: @@ -44,6 +44,7 @@ $( selector ).imageLightbox({
  button: false, // bool; show close button
  caption: false, // bool; show captions
  enableKeyboard: true, // bool; enable keyboard shortcuts (arrows Left/Right and Esc)
  + fullscreen: true // bool; enable fullscreen (enter/return key)
  gutter: 10, // integer; window height less height of image as a percentage
  offsetY: 0, // integer; vertical offset in terms of gutter
  lockBody: false, // bool; disables body scrolling when lightbox is open
  @@ -85,6 +86,10 @@ add an "ilb2-caption" data-attribute to the element, fallback value is the alt-a
  </a>
  ````
  +## Fullscreen
  +
  +Simply set the `fullscreen` option to true to enable the option. If the user's browser supports the fullscreen API, they can switch to fullscreen mode by pressing enter.
  +
  ## Hooks
  Image Lightbox now triggers unique events upon start, finish, and when either the next or previous image is requested.
  