/**
 * \brief Factory method to create metavalues with the right comments
 */
Metavalue	FITSKeywords::meta(const std::string& name,
			const FITSdate& value, const std::string& comment) {
	FITSKeyword	k = keyword(name);
	return Metavalue(name, k.index, value.showVeryLong(),
			(comment.size() == 0) ? k.comment : comment);
}
Metavalue::Metavalue(const std::string& _keyword, const FITSdate& d,
	const std::string& _comment)
	: keyword(_keyword), datatype(typeid(FITSdate)), comment(_comment) {
	value = d.showVeryLong();
	standardize();
}