support multi-leaders
update some functions to support multi-leaders
update socket.c
support multi-leaders
update utils.h
update server.c
update control.c
send torus leaders to whole torus
receive torus leaders info from control node
add print_torus_leader function
update utils.h
merge multi-leader
update .gitignore
update server.*
update utils.h
add leader flag in torus struct
update utils.h
update socket.c
update test.c
add heartbeat feature