---
* constructors and multi constructors now can be registered via
Configuration.add_constructor and Configuration.add_multi_constructor
decorators
* fix serious bug with factory and obj directives: previously they dropped away
nested objects such as lists and/or mappings
* configure_logging call now can be made inside config via !logging constructor
* Configuration.configure() now called inside
Configuration.{from_file,from_string,from_dict}() class methods, controlled
via configure=True keyword argument