UDP scanning

I added a function for UDP scanning. I've only tested it by starting a netcat server over udp as such: 

# Terminal A #
$ nc -l -u localhost 9999 

# Terminal B #
lmn@zmnd:~/code-master/MutiPortScan$ php ./MultiPortScan.php udp localhost 9998 10000 0
Commandline interface
=====================
Socket created 
Port range: 9998 -> 10000
Waiting for data ... 
Waiting for data ... 

# Terminal A #
lmn@zmnd:~$ nc -l -u localhost 9999
asdf <!-- typed this in
djfjf <!-- typed this in
pingpong     <!-- Sent from MPS script 


# Terminal B #
[port:9999] response <!-- Response is from 'asdf' and 'djfjf'
lmn@zmnd:~/code-master/MutiPortScan$