added robot to the gprs grammar as name

ps-grammar/gprs/gprs.jsgf

 #JSGF V1.0;
 grammar ToBI_GPRS;
-public <task> = [tobi] [(would | could) you] [please] <command> [please] [tobi];
+public <task> = [<robot_name>] [(would | could) you] [please] <command> [please] [<robot_name>];
+
+<robot_name> = tobi | robot;
 
 <command> = <bring_command> | <goto_command> | <find_command> | <follow_command> | <cleanup_command> | <show_command> | <pointat_command>;