Added a __deepcopy__() method to the Widget class in order to avoid a number...

Added a __deepcopy__() method to the Widget class in order to avoid a number of easy-to-trigger problems when copying Widget subclasses. Subclasses which are intended to have extra mutable fields should override this method. Refs #5505.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6450 bcc190cf-cafb-0310-a4f2-bffc1f526a37