dev-alert-json v1: adds http info on alert

Extends the JSON alert output to include the HTTP data,
added an extra data structure in json alert output

Previous pr: https://github.com/inliniac/suricata/pull/1092

- PR build: https://buildbot.openinfosecfoundation.org/builders/glongo/builds/0
- PR pcaps: https://buildbot.openinfosecfoundation.org/builders/glongo-pcap/builds/0