Pass old roles to set_user_role action. props awellis13. fixes #19134.

git-svn-id: http://core.svn.wordpress.org/trunk@23358 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Cast post_author to string in XML-RPC methods. props markoheijnen. fixes #22324.

git-svn-id: http://core.svn.wordpress.org/trunk@23359 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Display username (user_login) rather than user_nicename in Toolbar. fixes #22121.

git-svn-id: http://core.svn.wordpress.org/trunk@23360 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use digraphs for German umlauts in remove_accents(). props SergeyBiryukov, ocean90. fixes #3782.

git-svn-id: http://core.svn.wordpress.org/trunk@23361 1a063a9b-81f0-0310-95a4-ce76da25c4cd