Enhance SSH server options

An option I often use is missing, would be nice if it didn't require edit config file. I would think it is not uncommonly used, but maybe so.

MaxAuthTries - I often set this to < default of 6. The reason is I use iptables firewall to count number of syns for ssh, and, if above some limit, block the IP for a while. As opposed to installing other ssh brute force blocking software. Leaving it at 6 means user get 6 attempts to syn packet, that's too many for me. And it's easier and more efficient to use iptables than use denyhosts as well.

Probably a minor thing, but, thought I'd submit in case you want to do.