Update liveblog selectors for plupload.

Some IDs have been removed or changed to classes. This is a temporary fix until we figure out a more elegant way to handle this.
Use our oEmbed handling for uploaded images instead of an HTML img tag.

Also add appropriate line breaks around the image URLs to space things correctly.
Use "large" image size instead of full. The latter can be really really big sometimes.

Eventually, we will make this configurable.

See #24