NAME:
	KeywordStack.__init__
 PURPOSE:
	Initialize keyword_stack object
 CALLING SEQUENCE:
	result = KeywordStack( stack_yaml_file )
 INPUTS:
	stack_yaml_file		fully-qualified name of yaml file containing
						the dictionary of key definitions.
						Alternatively, the dict itself can be specified
						as input.
 OPTIONAL INPUT:
	ignore				list (?? unused)
 OUTPUTS:
	result				KeywordStack object
 PROCEDURE: