Updated README with GPIO

README.md

@@ -38,6 +38,7 @@ Telnet into the module and issue commands prefixed by +++AT to escape each comma
 +++AT FLASH # print current flash settings
 +++AT FLASH <1|0> # 1: The changed UART settings (++AT BAUD ...) are saved ( Default after boot), 0= no save to flash.
 +++AT RESET # software reset the unit
++++AT GPIO2 <1|0> # set GPIO2 pin HIGH or LOW (1/0)
 ```
 Upon success, all commands send back "OK" as their final output. Note that passwords may not contain spaces.
 
@@ -127,4 +128,4 @@ The following absolute path names and COM Port number are expected:
 C:\MinGW\bin;C:\MinGW\msys\1.0\bin in espmake.cmd
 C:\Python27\python in Makefile_VS2013 for flash
 COM5 in Makefile_VS2013 for flash
-```
+```