Pinger: Send a packet once every second with updated timestamp
Pinger: Implement server mode output

Print time, IP address, and sequence number when a packet is received in
server mode
Pinger: Remove unnecessary variable currentPacket in startClient()
Pinger: Make the server respond to client's packet, and make the client
print information about the packet and latency when it is received
Pinger; Show additional statistics after the client finishes
Pinger: Fix packet loss calculation
Pinger: Update the Makefile to remove additional '.class' files in the
'clean' target
README: Replace NetID usernames with CS usernames
Merge remote-tracking branch 'jdurbanek/master'
Iperfer: Allow sockets to reuse address
Iperfer: Remove bind() from client mode

This should have been done in server mode, but it is already done
implicitly by ServerSocket's constructor.