restore a compiling baseline
baseline network refactoring from patch 1966300
Move NetHandler to net, even though it still has some game aspects to it
Apply r17377 so it doesn't get lost
let it compile, for now
Make more Windows friendly, using SOCKET
Remove inappropriate dependency on bzfs
Merge -r 17261:17469 to stay close
Merged with r17474
merge r17526
Clean up NetHandler
Add first two protocol message classes (EchoRequest, EchoResponse)
Remove vestiges of kick logic from NetHandler.
Add fledgling ctor for client connections
disambiguate parameter and class member names
Excise client type from NetHandler
properly initialize extra info
Remove "socket" from the NetConnectedPeer "extra" structure.
Note that the coupling is still a bit tight, because the connection ID is
assumed to be to socket in the NetHandler (exposing too much implementation)
remove NetHandler::whoIsAtIP. It is based on an invalid assumption that only
one player is using a given IP (it really should return a collection of matches)
and it's only use in the code was suspect.
Remove unused NetListener::close methods
Eliminate an extra copy
stub client side support in NetHandler