New Version 0.5.2

fix a race that might have corrupted shares
net: tcp: disable the Nagle algorithm
  which reduces network latency in some circumstances
net: lower keepalive for nat-networks


I'm uploading this one earlier than planned because of the race I've found while doing the windows port. The race is unlikely and it seems nobody has hit it - however undefined behavior is always a bad thing. This version has some internal restructuring to simplify cross-platform development. It runs stable for me however be aware that it has more restructuring than usual.