* deprecated WikiEngine.getRequiredProperty( props, key ) in favour of 
   TextUtil.getRequiredProperty( props, key ). The former will be deleted in 2.10 scope

git-svn-id: https://svn.apache.org/repos/asf/incubator/jspwiki/trunk@1431022 13f79535-47bb-0310-9956-ffa450edef68