CALL_COMMAND_HANDLER macro

Use this to macro to call a command helper (or a nested handler). It provides command handler authors protection against reordering or removal of unused parameters. @b Note: This macro uses lexical capture to provide some arguments. As a result, this macro should be used @b only within functions defined by the COMMAND_HANDLER or COMMAND_HELPER macros. Those macros provide the expected lexical context captured by this macro. Furthermore, it should be used only from the top-level of handler or helper function, or care must be taken to avoid redefining the same variables in intervening scope(s) by accident.