Check for a WP_Error return from wp_create_user() in register_new_user().

props coffee2code.
fixes #14290.


git-svn-id: http://develop.svn.wordpress.org/trunk@25174 602fd350-edb4-49c9-b593-d223f7449a82
Test that passwords containing the username are penalised.

Tidy up some spelling, indentation and whitespace whilst we're at it.

Props iandunn. See #25088.


git-svn-id: http://develop.svn.wordpress.org/trunk@25175 602fd350-edb4-49c9-b593-d223f7449a82