Working version of the new config loaders for .py files and argparse.

Improvement to how config is handled in Components. When a Component gets a config object, it aways makes a deepcopy of it.

Fixing subtle bug in the traitlets with This. Previously subclasses This traitlets wouldn't accept superclass instances as values. I have added a this_class attribute to TraitletType that is set by the metaclass and is used later by This.validate to properly handle this case. I have also added new tests for this.

Important changes to simplify traitlets. Some aspect of traitlets were a bit too magical for us. Thus, we have simplified certain things to make it more straitforward: * Default values are always validated, but now, this is done when the HasTraitlets.__new__ is called. We used to do this the first time __get__ was called. * The klass argument of Type and Instance traitlets must be a class. Unlike enthought.traits, we are no longer accepting class names as str or instances. * The args and kw arguments to Instance.__init__ are now handled in better manner, but that is quite different from enthought.traits. * More tests of edge cases.

Adding testing for componenets.

Improvements to component.py. Components are now based fully on traitlets. The have a better querying interface and smart children, parent, root properties. Some testing has been added.

A few more small traitlets features.

Added casting versions of all the basic traitlet types.

Added support for Type and Instance traitlets with testing.

Merging upstream changes from trunk->module-reorg->inputhook.