fix rbtree node construction
implement rbtree::emplace
fix std::set emplace
fix std::map emplace
net: completion conditions updated to the current Boost.Asio signatures
net: implement read/write condition operations
net: fix socket::receive to return eof on stream sockets

fixes aa0a7866da
net: add WSAIoctl to read current socket options
sys read/write functions shall be implemented as transfer_all()
sys send/receive as write/read overloads
docs for sys read/write
add version for VC19 CTP2
vc19 has ceil at x86 too
add vc19 ctp3 version
add tr2 stream_mutex from N3535