Used for fast (on hash lookup) view searches: build('#view_id');

@param {string=} id New id value
@returns {string|view.Base} current id or self
function(id) {
        if (!arguments.length) { return this.dom().id; }
        if (this.dom().id) { view.unregisterId(this); }
        this.dom().id = id;
        view.registerId(this);
        return this;
    }