Include lightgallery media viewer in the core.

[kimisgold]

Provides files and view helper themes can use to display media files in lightgallery. The view helper allows for output that displays either the lightgallery viewer or a list of files that cannot be displayed within lightgallery. This should support images, html5 video, youtube, and pdfs.

[zerocrates]

Some remaining questions:

• thumbnails using data-thumb are probably not ever working, exThumbImage: 'data-thumb' needs to be passed to lightGallery init for that to work
  • if this does work, do we need the img inside the video div? or do we prefer to keep it so there's some content in there?
  • thumbnails for videos have code to check if the file has thumbnails and to use the fallback, other types don't (probably an unnoticed problem since those data-thumb attrs are dormant)
  • on the previous: it's annoying to get a thumbnail url for an file, instead of a thumbnail image tag which we have a helper for. should we just provide a record_image_url function?
  • Other Files seems a little underbaked: links go always to file pages, no thumbnails rendered. standard built-in themes just call file_markup on the array of files to display them, though I assume we don't want to do that either
  • media_caption setting has the problem of referencing "media" when we don't have that, also if it's lightGallery specific then it should probably have a lightGallery specific name: lightgallery_caption?

[kimisgold]

on the previous: it's annoying to get a thumbnail url for an file, instead of a thumbnail image tag which we have a helper for. should we just provide a record_image_url function?

I'd love record_image_url(), I'm pretty sure I've run into many other instances of not needing the full image markup, especially with third party jquery plugins.