WPMU Blog Name Restrictions Override

When non-site admins sign up for a new blog via the wp-signup.php page, they are subjected to the following restrictions on their site name (that site admins are not subjected to):

* No dashes are allowed.
* No underscores are allowed.
* The name can not be all numeric.
* Name must be at least 4 characters long

This plugin allows site admins to override each of those restrictions, toggling yes/no for the first three settings, and adding a minimum length for the name.

This plugin only affects blog creation via the sign up page. It does not affect blog creation via site admin -> blogs -> new blog