Merge changes I6abd2221,I2c149d29,I45d22857,I1f879b2c,If4986a25, ...

* changes:
  [PT06] Move setGlobalProxy into ProxyTracker
  [PT05] Move sendProxyBroadcast into ProxyTracker.
  [PT04] Move PacManager into ProxyTracker.
  [PT03] Move some more code into ProxyTracker.
  [PT02] Move static methods to ProxyTracker
  [PT01] Introduce ProxyTracker
  Remove a useless parameter.
  Small cleanup of Network.
  Cleanup of LinkProperties.