Fix: Ampersand operator in any position in selector issue in plugins

changed ampersand operator clearing condition with regex test

    api.plugin("hoverEffect", function(api, color) {
        return {
            "&:hover": {
                color: color,
                background: api.lighten(color, 60),
                ".ie8 &": {
                    color: "blue"
                }
            },
            ".ie8 &": {
                color: "#eee"
            }
        };
    });
    api.add({
        a: {
            color: "#000",
            hoverEffect: "#999"
        }
    });

result

    a {
      color: #000;
    }
    a:hover {
      color: #999;
      background: #f5f5f5;
    }
    .ie8 a:hover {
      color: blue;
    }
    .ie8 a {
      color: #eee;
    }

maybe this could be useful for those who arrange nested selector hierarchy differently


about usage of ampersand operator in yaml. the selector needs to be enclosed in quotes/double quotes to work.

    ---
    a:
      '.ie6 &':
    ...