1022 update1

- make asg1 final into linux-windows compatible
- fixed the bug when tcp conn. Pkt always shows "1" by changing the
seqNum as 1 in tcp conn instead of 0(original implementation
=== things to do ===
- change 'r', 'w' into 'c', 's'
- change recvInfo into concurrent mode
- add function to show the server information
=== problems to think ===
- how to know no. of UDP connection?