RakNet 2.41 has been released. From the user's perspective not much has
changed but internally a LOT has been rewritten.
1. Order of magnitude performance improvement. I'm estimating it's
about 5 times faster now.
2. Reduced memory requirement by about 25%.
3. Added plugin system, with a fully connected mesh plugin.
4. Fixed bug with not detecting duplicate packets when the packet
counter wrapped.
5. Added ID_CONNECTION_ATTEMPT_FAILED.
