Create and use struct rank.

Create and use struct rank.

2010-11-04  Sami Wagiaalla  <swagiaal@redhat.com>

	* gdbtypes.h: Create struct rank.
	Convert all 'BADNESS' macros to const struct rank declarations.
	(sum_ranks): New function.
	(compare_ranks): New function.
	* valops.c (find_oload_champ): Updated.
	(classify_oload_match): Use compare_ranks.
	Improved comments.
	(compare_parameters): Use compare_ranks.
	* gdbtypes.c: Initialize 'BADNESS' constants.
	(sum_ranks): New function.
	(compare_ranks): New function.
	(compare_badness): Use compare_ranks.
	(rank_function): Use global constants instead of literals.
	(rank_one_type): Ditto.
	Return struct rank.
	Use sum_ranks.