Import from wordpress

This branch creates a hidden action in the blog module that lets you import a wordpress export file. It will insert blogposts and comments in the fork blog module, and download the images from the original wordpress to the  frontend/files/userfiles/images/blog directory, replacing any links to them in the blogposts with correct links to their new location. The imported blogposts will be assigned to existing fork users with the same email address as the original creator of the post. If that user doesn't exist, the post is assigned to the fork admin user.