Add datatypes to represent metamodels, elements and links. They will be used later to move implementation of links and collections of elements into abstract layer.
Add datatypes to represent metamodels, elements and links. They will be
used later to move implementation of links and collections of elements
into abstract layer.


git-svn-id: 84a7e9580ef41fb6fdf7e69fc6952b9cdfe895dd@1805 661adc5f-87f8-0310-85d6-9a7b5f58d823

reznikmm/matreshka,reznikmm/matreshka,reznikmm/matreshka,reznikmm/matreshka,reznikmm/matreshka,reznikmm/matreshka