Adding the unified2 analyzer.

- This isn't connected to anything yet.
Pluginizing the DNP3 analyzer, plus a basic script logging requests
and replies.

Almost ready, but now 1 test fails again ...

[Note I broke git history by copying over the files into a new branch.]
Add debugging code to find FP inconsistency.
Merge remote-tracking branch 'origin/master' into topic/seth/sumstats-updates
Update baseline with now correct FP tests.
Remove debugging code.
Merge remote-tracking branch 'origin/master' into topic/seth/unified2-analyzer

Conflicts:
	src/CMakeLists.txt
Merge branch 'master' into topic/robin/dnp3-merge-v3

Conflicts:
	scripts/base/init-default.bro
Unified2 file analyzer updated to new plugin style.
Merge remote-tracking branch 'origin/master' into topic/seth/unified2-analyzer
levenshtein distance
Fixing well-known port.

This fixes the remaining test.
added condition to check DNP3 packet without app layer data

Conflicts:
	src/analyzer/protocol/dnp3/DNP3.cc
added a test case for dnp3 packets with only link layer
Tiny bit of cleanup and adapting the new test.
Merge branch 'topic/robin/dnp3-merge-v3'

Includes a bit more docs/comments cleanup. We should eventually
document the events further but it should suffice for now.

* topic/robin/dnp3-merge-v3:
  Tiny bit of cleanup and adapting the new test.
  added a test case for dnp3 packets with only link layer
  added condition to check DNP3 packet without app layer data
  Fixing well-known port.
  Pluginizing the DNP3 analyzer, plus a basic script logging requests and replies.
Updating submodule(s).

 [nomail]
Working unified2 analyzer.

 - No output by default yet.  Most of the activity is centered
   around generating the Unified2::alert event which ties together
   an IDSEvent and a packet.
Fixed some tests.
Fixing bug in DNP3 analyzer flagged by compiler warning.