added fwknop-2.5 release date
[client] added --use-hmac to --help output (noticed by Damien)
ChangeLog.git file now shows changes since 2.0.4
[libfko] set version-info to 2:0:0 per Damien and Franck's recommendations
set libfko version to 2.0.0 for the RPM per Damien's recommendation