Log API v4.0

Changes since https://github.com/inliniac/suricata/pull/776:
- addition of FiledataLog API
- convert 'file-store' to FiledataLog API

Prscript:
- PR build: https://buildbot.suricata-ids.org/builders/inliniac/builds/142
- PR pcaps: https://buildbot.suricata-ids.org/builders/inliniac-pcap/builds/62