introduced new feature "ban time exponential increasing":
   "bantimeextra.enabled" in jail.conf allows to use database for searching of previously banned ip's to increase a default ban time using special formula,
   by default, each next ban it will be original banTime * 1, 2, 4, 8, 16, 32...
see "jail.conf" for some other options of "bantimeextra";
additional we can configure a little randomization of ban time, to prevent "clever" botnets calculate exact time IP can be unbanned.
WARNING: by first start the server upgrades sqlite database (table "bans" will recreated with another schema);