Syntax: %bSET GSM <GSM number|->%b

Sets the your GSM number to <GSM number>. When users perform 
an %bINFO%b on your nickname, they will be informed of 
your GSM number, unless you set %bHIDE%b ON. 
To clear your GSM number use a "-" as the parameter.
Examples:
         %b/msg %N SET GSM +385 91 1234567%b
           Sets your GSM to "+385 91 1234567".

         %b/msg %N SET GSM -%b
           Clears your GSM number.
