[preview] mpm optimization v0.35

Clean up of https://github.com/inliniac/suricata/pull/1214

Mostly commit cleanup, reshuffling, message rewording.

Prscript:
- PR build: https://buildbot.openinfosecfoundation.org/builders/inliniac/builds/81
- PR pcaps: https://buildbot.openinfosecfoundation.org/builders/inliniac-pcap/builds/81

cc: @ken-tilera
Yes, this code was changed when converting ac-tile to use local pattern indexes instead of global PIDs. the ctx->parray[i]->id should be replaced by just "i". fixed in PR 1270.