Add CSS support for attribute selector

 http://www.w3.org/TR/css3-selectors/#attribute-selectors

Need to support e.g., [direction='rtl']

Possible implementation would be to add code to implementations of com.sun.java.css.Property that would invoke some method in css when the property invalidated or set. This needs to be done in a way that there is no listener added to the javafx.beans.property.Property. If there is no attribute selector for the property, then the css method shouldn't be triggered. Something like:


    @Override
    protected void invalidated() {
        super.invalidated();
        if (isAttributeSelector && triggerValue.equals(String.valueOf(get())) {
            // get the node for this javafx.beans.property.Property
            // set the node's cssFlag to UPDATE
        }
    }