User picture improvements in node template

Problem/Motivation

If user pictures are enabled but no user picture is set an empty <article> wrapper prints in node template. Additionally even when there is a user picture the article is untitled.

Proposed resolution

1. Prevent empty markup printing.
2. Remove the article wrapper entirely (however we do that, this should happen).
3. Consider a method for getting the user/author picture directly without any wrapper markup, this should be a renderable array.

Remaining tasks

Discuss and patch.

User interface changes

None.

API changes

None.