Shinji Kagawa dashed over to the dugout, high-fived his coach Jürgen Klopp and a couple of teammates before searching out Felipe Santana in particular. It was their special day after all.   Before Saturday’s game against Werder Bremen, the Borussia Dortmund players had gathered around the pair and sang ‘Happy Birthday’ in the dressing room. After eight minutes, Kagawa had opened the scoring. It was the icing on the cake and he wanted to blow the candles out with Santana.   “I got myself a present today,” he said. “It’s his birthday as well and I’m happy that I was able to dedicate my goal to him.”   The afternoon had started on a somber note. A minute’s silence was held in memory of…