Dev log api v1.8

Continuation of work in https://github.com/inliniac/suricata/pull/701

Changes:
- This completes the DNS port.
- Address minor issues by @regit.
- Still need to revisit registration.

Build logs:
- PR build: https://buildbot.suricata-ids.org/builders/inliniac/builds/95
- PR pcaps: https://buildbot.suricata-ids.org/builders/inliniac-pcap/builds/16

cc: @regit @poona @decanio @ken-tilera