As suggested by Markus Elfring, a few "const char *" have replaced
some "char *" declarations where a function is not expected to
modify a value. It does not change the code but it helps detecting
coding errors.
It is now possible to tarpit connections based on regex matches.
The tarpit timeout is equal to the contimeout. A 500 server error
response is faked, and the logs show the status flags as "PT" which
indicate the connection has been tarpitted.
