When a contact is added, her personal blog will also be added automatically.
Also, when a new identity is added, a personal blog for that identity is created.
Part of #436
Removes teaser and makes body mandatory.
It also adds support for deleting blogs and
introduces a getAuthorStatus() method to the IdentityManager
that takes a running transaction.
This implements a simple initial blog client that covers the basic blog
actions, but no deletion/removal of blogs, yet.
Classes for Blogs and Blog Post Headers have been introduced along with
the associated factories.
A `BlogPostValidator` has been added that validates incoming blog posts.
Closes#402Closes#404
