function StateCore(src, md, env) {
		this.src = src;
		this.env = env;
		this.tokens = [];
		this.inlineMode = false;
		this.md = md;
		// link to parser instance
	}
Token.attrJoin(name, value)

Join value to existing attribute via space. Or create new attribute if not
exists. Useful to operate with token classes.