Added a bunch of Grok patterns for Cisco ASA firewall syslog messages.
* Confirmed to work:
  ASA-6-106015
  ASA-1-106021
  ASA-4-106023
  ASA-5-106100
  ASA-6-110002
  ASA-6-302010
  ASA-6-302013
  ASA-6-302014
  ASA-6-302015
  ASA-6-302016
  ASA-6-302020
  ASA-6-302021
  ASA-3-313001
  ASA-3-313004
  ASA-4-313005
  ASA-3-313008
  ASA-4-402117
  ASA-4-402119
  ASA-4-419002
  ASA-6-602303
  ASA-6-602304
  ASA-6-713172
  ASA-4-733100
* Based on patterns found here(https://gist.github.com/dav3860/5345656) and documentation here(http://www.cisco.com/en/US/docs/security/asa/syslog-guide/logmsgs.html#wp4771036)
  ASA-2-106001
  ASA-2-106006
  ASA-2-106007
  ASA-2-106010
  ASA-3-106014
  ASA-4-419001
  ASA-4-500004
  ASA-6-305011
  ASA-7-710001
  ASA-7-710002
  ASA-7-710003
  ASA-7-710005
  ASA-7-710006
List all matched message codes in the Grok names to help troublshoot parse failures
Add a Grok expression for the base part of the Cisco ASA syslog message
Merge pull request #610 from GregMefford/master

Added a bunch of Grok patterns for Cisco ASA firewall syslog messages.