Modifications to the metrics framework API and new features.

- Metrics:ID enum has been replaced with strings.

- Uniqueness can now be measured with the Metrics::add_unique function.

- Filters can change the index value with the $normalize_func field.
Ported scripts using metrics framework and added a new smtp script.

- New script measures a couple of aspects of SMTP traffic.

- Existing metrics scripts had a small amount of work done
  to make them work with changes to metrics framework.
Cluster support for the metrics framework returns and all tests work again.
Some scripts for collecting connection stats and "app" stats.

- App stats are considered stats for applications on the internet.
  Services like facebook, youtube, etc.
The app metrics break interval is now configurable.
Merge remote-tracking branch 'origin/master' into topic/seth/metrics-updates

Conflicts:
	testing/btest/Baseline/scripts.base.frameworks.metrics.basic-cluster/manager-1.metrics.log
	testing/btest/Baseline/scripts.base.frameworks.metrics.basic/metrics.log
	testing/btest/Baseline/scripts.base.frameworks.metrics.cluster-intermediate-update/manager-1.notice.log
	testing/btest/Baseline/scripts.base.frameworks.metrics.notice/notice.log
	testing/btest/scripts/base/frameworks/metrics/basic-cluster.bro
Added function to intercept threshold checking
Added the branch /testing
Started the branch testing2
Added str to pred function
Merge branch 'master' into topic/seth/metrics-merge
Metrics framework checkpoint.

 - New scan.bro merged in and reworked a bit.

 - Updated metrics API.  Now possible to calculate much more.
Merge remote-tracking branch 'origin/master' into topic/seth/metrics-merge
Updated the app-metrics script to the new metrics api.

- Inconsequential change to scan.bro.
Implemented a nearly generic Queue in scriptland.
More cleanup and fixed to the metrics framework.
Added a script module for detecting hosts doing traceroutes.
Updated the SQL injection detection script to make it include samples in notice emails.
Some test updates.
More test updates.