ROTTERDAM (Reuters) - Royal KPN NV, the largest Dutch telecommunications company, on Wednesday reported better than expected fourth quarter earnings but disappointing growth guidance for 2020 knocked its shares lower. CEO Joost Farwerck, who took the top job in October amid a wider overhaul, said he will continue with plans to cut costs while investing in fibre optic and 5G networks.Competition from the likes of T-Mobile and Vodafone-Ziggo were "reflected in lower net (subscriber) adds in..