Distributed Leader-following Swarm of Heterogeneous Multi-agent Systems* *This work is supported by the National Natural Science Foundation of China under Grant Nos. 61074125, 61104140, 61004093, and 61073102, the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (No. 61221003), the National Key Basic Research Program (973 Program) of China (No. 2010CB731403), the Research Fund for the Doctoral program of Higher Education (REDP) under Grant No. 20100142120023, and the Program for New Century Excellent Talents in University from Chinese Ministry of Education under Grant NCET-12-0215.