add class send_delta
add comments
remove ssl_service()
add comments
command send_delta finished
send_deletion finished
send_addition finished
add finish_bak_task
finished backup
update .gitignore
add task_lock
add lock on project
call fixed prepare() after locked
fix possible deadlock
implemented client_get_prj
use -pthread instead of -lpthread
implemented client_get_time_line
update config_path
fix bug: forgot to unlock before return
pass -f option to /bin/rm