Log Message:
Updated to 2.1.4

Aug 3, 2020: 2.1.3 improved --bison-bridge option; updated examples.
Aug 19, 2020: 2.1.4 changed IN_HEADER to yyIN_HEADER when --flex is used with \ 
--header-file; added reflex::Input::Handler event handler for custom handling of \ 
FILE* errors and non-blocking FILE* streams.