Summary Update

This update was mainly for my own ease of use, but some of the changes will be useful to all.

* Open Graph metadata and preview image was added to the post model, for sharing on other sites and apps with a preview image.

* Playlist now uses album names as anchors instead of album IDs, to stop them breaking on page update. Yeah, that should have been how it worked from the beginning, but I'm only one man with a lot of ideas. They can't all be gold.

* A few CSS tweaks.

That's about it for this one.