Fix forward error: invalid byte sequence in UTF-8 (2nd try)

Continued from the pull request #2. 

Now, the invalid byte sequence is replaced with `?`, and the replacement occurs only when ArgumentError (invalid byte sequence in ***) is raised. 
In addition, non-utf8 byte and `reserve_data` option is supported.  

BTW:

I think `e.message.index("invalid byte sequence in") == 0` is not a clean code, but I could not find another way to rescue the invalid byte error. Any thoughts?