i18nise a couple of strings while I was there.

Move the preview window functionality out into a separate file, so it can be reused elsewhere (Export UI is using it).

We can use this to apply certain styles when javascript is around - most notably, to have stuff that is shown when javascript is off, but hidden by default when it is on.

There are two classes provided to help with this: js-hidden and nojs-hidden. They hide the element they're applied to when javascript is on or off respectively.

The previously global constants used to specify what to export are now class constants, and are stored in the class so that plugins can check what they were set to.

This page presents a choice of export format, and whether to export everything or just a list of views. It simplifies the UI by hiding the view selector if javascript is enabled.

This requires a bit of fiddling - we actually secretly grab the folders that all the files are in when doing granular export, regardless of whether they've actually been selected for export. This is so all the files are exported in the correct folder structure.

Fix HTML validation issue in recent blogposts and reorder parameters so the HTML export can rewrite its links.

(#3270) Prevent crashing when a logged out person visits a public view that has been submitted for assessment.
(cherry picked from commit ac1730b6)

This makes sense, as people may have data in them and they will still want to get at that data even if their administrator disables the plugin.
(cherry picked from commit 61a608972d8a86daec2919a439533af826114021)

It now works the way it worked for import. If the file exists, it has to implement the class. If the plugin doesn't want to implement it, it doesn't provide the file.

Don't use disabled artefact plugins when exporting HTML - if they're disabled, their data won't be in the export.

Uses a new helper class to do the gruntwork, and a lot of preg_replace stuff. It's a little bit hacky perhaps, but it's the simplest thing that could possibly work.

Not sure how people were downloading attachments from blogposts in view before this.

This patch ditches use of the tablerenderer in favour of just showing the most recent posts, and linking off to view/artefact.php for the rest. I added pagination to assist that.

Needs cleanup for sure, but for now it's there and it works.

I've not touched some strange things I saw while doing this, such as the 'resumefive' and 'resumefour' classes on the tables. I can only assume they're used somewhere, although grep gives no clues.