Based on CVS version from Ralf Lübben.
Changelog:
- IPv6 Accounting fix by Comic Chang
- iroute netmask computation fix by Samuel Thibault
- IPv6 support patches by Samuel Thibault
- Configurable Acct-Interim-Interval
- Asynchronous client-connect and instant client-disconnect (requires OpenVPN patch by Fabian Knittel, https://github.com/fknittel/openvpn/tree/feat_deferred_client-connect)
- Various thread-safety fixes