HAL_SITL: make model name case insensitive

libraries/AP_HAL_SITL/SITL_cmdline.cpp

@@ -153,7 +153,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
 
     if (model_str && home_str) {
         for (uint8_t i=0; i<sizeof(model_constructors)/sizeof(model_constructors[0]); i++) {
-            if (strncmp(model_constructors[i].name, model_str, strlen(model_constructors[i].name)) == 0) {
+            if (strncasecmp(model_constructors[i].name, model_str, strlen(model_constructors[i].name)) == 0) {
                 sitl_model = model_constructors[i].constructor(home_str, model_str);
                 sitl_model->set_speedup(speedup);
                 sitl_model->set_instance(_instance);