State Key Laboratory of Software Development Environment and Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education and Research Institute of Beihang University in Shenzhen, Beijing, China. xuyan04@gmail.com.|Microsoft Research, Beijing, China.|Microsoft Research, Beijing, China.|Microsoft Research, Beijing, China.|Microsoft Research, Beijing, China.|Department of Pathology, School of Medicine, Zhejiang University, Hangzhou, China.|Microsoft Research, Beijing, China.