cdist/doc/dev/todo/post-1.3

Core:
   - allow redefine object, if everything same
   - support $__self = relative_type/object_id
   - .cdist
   - cache
   - display changes if object cannot be merged to user

Cache:
   Assume you want to configure stuff one host ("monitor node"),
   depending on the configuration of other hosts ("cluster nodes").

   For instance, the monitor host would like to know,
   which hosts are configured with the provider
   "apache" and option --start true.

   This requires the monitor node to be able to
   query all other configured nodes. It can't
   ask for all hosts, because cdist does not
   know which hosts are configured or may exist.

   Example implementation

   If cdist keeps ("caches") the configuration of every
   node it configures, each new node can query the
   cache for existing nodes that acquired the given
   configuration.

Types to be written/extended:
   - __ssh-keys (host/user)
   - __service
   - __file_edit
      - regexp replace (can probably cover all?)
         -> aka sed.
   - __cron