public Config(Map<String, String> config) {
		if(config == null)
			throw new NullPointerException();
		for(String key : config.keySet())
			if(key == null)
				throw new IllegalArgumentException("Null key in config");
			else if(config.get(key) == null)
				throw new IllegalArgumentException("Null value in config");
		this.config = Collections.unmodifiableMap(new HashMap<String, String>(config));
	}