ESP8266 commands
   AT version:0.30.0.0(Jul  3 2015 19:35:49)
   SDK version:1.2.0
   Ai-Thinker Technology Co.,Ltd.
   Build:1.2.0.A Aug  7 2015 17:21:44
\r\n
   enter carriage return, newline
general
   reset
      AT+RST\r\n
   get version
      AT+GMR\r\n
   update firmware
      AT+CIUPDATE\r\n
join access point
   station mode
      AT+CWMODE=1\r\n
   list access points
      AT+CWLAP\r\n
   join access point
      AT+CWJAP="access_point_ssid","access_point_password"\r\n
   list IP address
      AT+CIFSR\r\n
become access point
   mode: 1=station, 2=access point, 3=both
      AT+CWMODE=2\r\n
   set SSID, password, channel, encryption (0 = open)
      AT+CWSAP="SSID_name","password",3,0\r\n
   set IP address
      AT+CIPAP="192.168.1.1"\r\n
   list stations
      AT+CWLAP\r\n
   set DHCP, 0=access point/1=station/2=both, 0=enable DHCP/1=disable
      AT+CWDHCP=0,0\r\n
TCP client: get Web page
   multiple connection mode for TCP
      AT+CIPMUX=1\r\n
   open TCP connection 1 to fab.cba.mit.edu port 80
      AT+CIPSTART=1,"TCP","fab.cba.mit.edu",80\r\n
   send Web page request on connection 1, with character count
      AT+CIPSEND=1,50\r\n
      GET /test.html HTTP/1.1\r\n
      HOST: fab.cba.mit.edu\r\n
      \r\n
   close connection 1
      AT+CIPCLOSE=1\r\n
TCP server: send Web page
   multiple connection mode
      AT+CIPMUX=1\r\n
   start TCP server, on port 80
      AT+CIPSERVER=1,80\r\n
   send Web page reply on connection 0, with character count
      AT+CIPSEND=0,44\r\n
      HTTP/1.1 200 OK\r\n
      \r\n
      <html><body>hello world\r\n
   close connection 0
      AT+CIPCLOSE=0\r\n
UDP client/server
   multiple connection mode
      AT+CIPMUX=1\r\n
   open UDP connection 1, to 192.168.1.11, remote port 1234, local port 1234, 0/2 = remote will not/will change
      AT+CIPSTART=1,"UDP","192.68.1.11",1234,1234,0\r\n
   send on connection 1, with character count, to 192.168.1.11, port 1234
      AT+CIPSEND=1,5,"192.168.1.11",1234\r\n
      hello
   close connection 1
      AT+CIPCLOSE=1\r\n