Config::Model::Itself module is a plugin for cme which provides a
 Perl/Tk graphical interface to edit configuration models that are be
 used by Config::Model.
 .
 Config::Model::Itself also provides a model for Config::Model
 (hence the Itself name, you can also think of it as a meta-model).
 The model editor will use this meta-model to construct the graphical
 interface so you can edit the configuration model for *your*
 application. [ Config::Model::Itself is the "eat your own dog food" principle
 applied to Config::Model ;-) ]
 .
 Let's step back a little to explain. Any configuration data is, in
 essence, structured data. This data could be stored, for instance, in
 an XML file. A configuration model is a way to describe the structure
 and relation of all items of a configuration data set.
 .
 This configuration model is also expressed as structured data. This
 structure data is structured and follows a set of rules which are
 described for humans in Config::Model.
 .
 The structure and rules documented in Config::Model are also expressed
 in a model in the files provided with Config::Model::Itself.
 .
 Hence the possibity to verify, modify configuration data provided by
 Config::Model can also be applied on configuration models.
 .
 The model editor program launched with "cme meta edit"