Strict typing for YAML
New access pattern requires to specify the expected type, i.e. 'scalar', 'list', or 'dict'. This ensures that the node offers the expected functionality instead of polluting 'tNode' with dummy functions which throw error messages if not overwritten.
The restructuring of the code allows to hierarchically construct methods without much code duplication.
Some aspects of the error messaging system have been improved.
Martin Diehl