Add option to prepopulate the Title field

Hi.

The following patch adds a new option to the node form which allows admins to choose that the title field should be prepopulated with the pattern.

This is more userfriendly, as some users are left wondering what will happen if they don't give a title to their node. This solves this issue.

This will obviously not work well with token replacements, but could still be handy in many situations.