Log Message:
Update to 0.9.15. Changes since 0.9.14:

- Make the Prelude-LML UDP server IPv6 compatible.
- Implement 'idmef-alter' and 'idmef-alter-force' option, alloing
  to include static values into IDMEF events generated using a given
  format.
- New PPP/PPTPD/L2TP ruleset, by Alexander Afonyashin <firm <at> \ 
iname.com>,
  with slight modification from Pierre Chifflier <p.chifflier <at> \ 
inl.fr>.
  Close #340.
- Fix CISCO VPN ruleset so that the 'Authentication rejected' rule will
  trigger even if the 'server' field does not contain a word (fix #328).
- Remove dos-style end-of-lines (Closes #338)
- Fixes possible off by one when parsing variable reference number, and
  remove un-needed check that would always evaluate to TRUE.Thanks
  Steve Grubb <sgrubb <at> redhat.com> for reporting this problem (and
  running flexelint on the Prelude sources)!
- Update for libtool 2.x compatibility.
- This simplify the whole regular expression handling a lot, making the
  code much easier to read, and fixing potential problem with ovector
  assignement. This code should also improve performance by a small
  factor.
- Change CISCO references urls to their new location, add CISCO ASA rule
  to handle discarded tcp or udp packets.
- Various fixes and update.