typo in contacts.h

[lzhelyaskov]

one of positionEpsilon should probably be velocityEpsilon

        /**
         * Returns true if the resolver has valid settings and is ready to go.
         */
        bool isValid()
        {
            return (velocityIterations > 0) &&
                   (positionIterations > 0) &&
                   (positionEpsilon >= 0.0f) &&
                   (positionEpsilon >= 0.0f);
        }