Add --demangle and --no-demangle options:

	Add --demangle and --no-demangle options:
	* gprof.h (demangle): Declare.
	* gprof.c (demangle): New global variable.
	(OPTION_DEMANGLE, OPTION_NO_DEMANGLE): Define.
	(long_options): Add "demangle" and "no-demangle".
	(usage): Mention --demangle and --no-demangle.
	(main): Handle OPTION_DEMANGLE and OPTION_NO_DEMANGLE.
	* utils.c (print_name_only): Only demangle symbol name if demangle
	is true.
	* gprof.texi (Output Options): Document new options.