TODO for PyBal

* Resolve hostnames to IPs at startup, and then use IPs
  exclusively for monitoring / LVS state modification, so it's
  more robust when the DNS resolver is flaky
* IRC notification
* An ICMPReachability monitor that checks whether the realservers
  are actually reachable *on their service IPs* - requires
  Twisted Pair or python-eunuchs for creating non-routed raw
  IP packets
* (Partial) lvsmon-like configuration from textfiles retrieved
  from the realservers, e.g. for computing the weight of a realserver
* Reimplement IPVSManager using Netlink once the IPVS Netlink interface
  has entered the kernel
* Revisit the whole config parsing wrt consistency and security
* Syntax errors in server lists cause unhandled Deferreds, and appear
  to stop any further config rereads - this needs to be fixed.