Initial introduction of Value and Range in AllowedValues, update zcfg documentation. Return valid Status code when returning ExceptionRepport.

git-svn-id: http://svn.zoo-project.org/svn/trunk@459 4b6b6ad6-68b3-4dcc-9231-bd9b83bc5dc3
Small fix in doc.

git-svn-id: http://svn.zoo-project.org/svn/trunk@460 4b6b6ad6-68b3-4dcc-9231-bd9b83bc5dc3