Sable Error messages patch

[Nadir.BOUSSOUKAIA@st.com]

     Hi,
     
     Is someone interested on my patch on the SableCC code that displays 
     the token's text values (when it's possible) rather than the token 
     names in the error messages given by the generated parsers ?
     
     for exemple if you define if="if" in your grammar, user would 
     initially get "Tif required" as error message. That patch change that 
     to "'if' required'. Same for '=' instead of 'Tequal' for example..
     
     Regards,
     Nadir