Add a commenting system

[outworlder]

Commenting System

The comment system is not yet functional. It should allow for users to create new posts and preview them before submission.

Required features

• Post comment form
• Form validation (email, content)
• Supporting database tables
• "Blog owner post"
  Only when the blog administrator is logged in, should allow the creation of a "special" post. This post is marked (visually) in a different way.

Optional features

• Comment moderation
  Should allow comments to be edited and removed. Moderated posts are also possible, requiring approval by the author.
• Trackbacks/pingbacks
• Quoting (of other user's comments)
• Markdown
• Syntax highlighting for code
• Github integration
• Gravatars
• OpenID login
  If implemented, should allow editing and removal of posts created by the logged-in user.