Handle multi-level typenames and implicit typename in base list.

Handle multi-level typenames and implicit typename in base list.

	* parse.y (typename_sub{,[0-2]}): New rules.
	(structsp, rule TYPENAME_KEYWORD): Use typename_sub.
	(nonnested_type): New rule.
	(complete_type_name): Use it.
	(base_class.1): Use typename_sub and nonnested_type.
	(nested_name_specifier): Don't elide std:: here.
	* decl.c (make_typename_type): Handle getting a type for NAME.
	(lookup_name_real): Turn std:: into :: here.

	Rvalue conversions were removed in London.
	* call.c (is_subseq): Don't consider lvalue transformations.
	(build_conv): LVALUE_CONV and RVALUE_CONV get IDENTITY_RANK.
	(joust): Reenable ?: kludge.

From-SVN: r15715