Rename remove_value() to delete_value()
for consistency with delete_child()
Add delete() method to Session.
Remove path validation from Session.exists()
It's not only redundant, but also breaks checking
paths that are incomplete from set() point of view,
but otherwise perfectly valid.
Add more Session.delete() tests.
Add "multi" attribute to the interface definition schema.
Add ConfigNode.set_value() method for a more convenient way to update non-multi nodes.
Add "multi" attribute support to the reference tree loader.
Add PathValidator.check_node() method, a loophole for executing
arbitrary functions on reference tree nodes.
Make set work with multi nodes, update tests accordingly.