** Added allowTopicCreation property into Forum entity (determines
whether topics are allowed to be created by users into the forum)
** Enabled security interceptors in common project
** Added support for adding context based permission checks
** Renamed PermissionContext as SecurityContext
** Added support for determining context as el expression into
SecurityContext
** Added support for message for SecurityException
** Added permission check that checks whether users are allowed to
create new topics for forum or not
** Moved permission checking from ForumController into backing beans so
the controller methods would be more generally usable
** Removed new topic button from forum when topic creation is not
allowed