Implemented ./client/file_monitor

1. Implemented file_monitor with inotify.
2. Modified and Merged send_packet and recv_pack to ./server/
   and ./client/.
3. Created ./utility/ directory so that to maintain common
   utilities such like segment operation and linked list.

Signed-off-by: Hongyi Jia <Hongyi.Jia.GR@dartmouth.edu>