added osx specific ipfw action with random rulenum
Merge branch 'osx-ipfw' of https://github.com/afragen/fail2ban into osx
DOC: credits and thanks for Andy for osx-ipfw
ENH: more options and ruggedness to prevent unintensional consequences
ENH: added jail.conf example. closes gh-340
BF: reverted to simplier random rulenum. If your machine is handling 1000s of block the addition complexity isnt what you want
ENH: port optional
add mods from grooverdan and fix actionunban

actionunban still not working in grooverdan's mod. I made this one grep both <ip> and <port>. It should be more specific if the same <ip> is banned on multiple ports.
more specific actionunban
after some research it looks like setting to unreachable better than deny
MRG: resolve conficts in action.d/osx-ipfw design
Merge pull request #344 from grooverdan/osx

ENH: OSX ipfw based on Andy Fragen's work