TST/ENH: Improve regex around exim

rejected by local_scan now has test cases.

Unrouteable address error messages now normalised after looking into
exim code.
ENH: new exim filter regexs. Also note a begining PID in this format. Thanks to ftoppi for the log entries
DOC: credits/blame to me for changes to exim
Merge branch 'exim' of https://github.com/grooverdan/fail2ban

* 'exim' of https://github.com/grooverdan/fail2ban:
  DOC: credits/blame to me for changes to exim
  ENH: new exim filter regexs. Also note a begining PID in this format. Thanks to ftoppi for the log entries
  TST/ENH: Improve regex around exim
BF: make colon after [daemon] optional.  Close #267
Merge branch 'master' of git://github.com/fail2ban/fail2ban

* 'master' of git://github.com/fail2ban/fail2ban: