Ban time incr

New feature "automatically exponential increasing ban time".
WARNING: by first start the server upgrades sqlite database (table "bans" will recreated with another schema);
Option "bantime.increment" 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 increase banTime * 1, 2, 4, 8, 16, 32...
see "jail.conf" for some other options of "bantime.___";
additional we can configure a little randomization of ban time, to prevent "clever" botnets calculate exact time IP can be unbanned.

Version _3_ was never released, so don't expected there are many people using it. Also, the update script for _3_ doesn't update the version number as far as I can tell, so version will be at _2_ anyway. I think my point is we don't want to keep increasing the version number every time something is changed in a pull request, as this will lead to many update scripts which risks bugs creeping in.

It's just a number as you say, so happy to leave at _4_, but for consistency think the _3_ update script should be fixed.