Open UserAuthenticationData for arbitrary value types (VFS-466). Change requires new getter and setter of the data, deprecate old methods.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/vfs@1450670 13f79535-47bb-0310-9956-ffa450edef68
Update changes.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/vfs@1450672 13f79535-47bb-0310-9956-ffa450edef68
Fix error handling for type mismatches with UserAuthenticationData.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/vfs@1450686 13f79535-47bb-0310-9956-ffa450edef68