Display link previews

[TomboFry]

When a URL is included in the post - either as part of a like or bookmark post, for example, or included within the post's content - microlight should attempt to load the page details automatically and cache them in a database so that a preview for the link can be shown.

It would also be very handy if YouTube, SoundCloud, Bandcamp, etc. content could be embedded directly into the page, although this would require URL parsing of specific domains.