Textpattern_Tag_Registry::registered() to getRegistered().

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5802 2fea6a4d-a838-0410-917b-93a53c48e9d2
Example formatting.

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5803 2fea6a4d-a838-0410-917b-93a53c48e9d2
Not just some tag.

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5804 2fea6a4d-a838-0410-917b-93a53c48e9d2
Type hint in Textpattern_Tag_Registry::process().

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5805 2fea6a4d-a838-0410-917b-93a53c48e9d2