Make exception handling an optional feature about jpcre2

[neurobin]

Exception handling is completely removed (As of 10.26.01). As regex operation itself is heavy, I just couldn't convince myself to keep something as expensive as exception.

At it's current condition, there's no need to worry about errors any more. Error messages, codes are only helpful for debugging or experimentation.

Though there's still the possibility that someone might want to use the error codes to interact with users, for that the error handling functions associated with the jpcre2::Regex class is more than enough. If that is required, then do remember to make use of resetErrors() function. :D