PlayPlugin has wrong implementation of compareTo

[niels]

The compareTo method of PlayPlugin ignore the rule that if a.compareTo(b) == 0 should follows a.equals(b). So I would recommend to replace it with the following
    /**
     * {@inheritDoc}
     */
    public int compareTo(PlayPlugin o) {
        final int result = (index < o.index ? -1 : (index == o.index ? 0 : 1));
        if (result == 0) {
            return this.getClass().getName().compareTo(o.getClass().getName());
        } else {
            return result;
        }
    }

I forget this in some projects and it cost me lot of time to find the bug, if someone rely on this, which happens at least in groovy maps.