Implement a high-level "server" and "client" class abstractions.

[madmaxoft]

These should provide an easy interface for making a TCP server and client. The interface should be based on callbacks that the class calls for various events - new connection, available incoming data, connection closed etc.
The classes should use whatever underlying OS-dependent API they need to provide reasonable responses with little to no limits (such as the select's fd limit on *nix).

Then, we can export this interface to Lua to provide the much needed async networking to the plugins.

[worktycho]

Might it be better to go for an external library. Given that the networking TS for the standard library is based on Boost.Asio we might want to go for that. http://think-async.com/Asio/AsioAndBoostAsio is a project to extract the Boost.Asio code to work independently from the rest of boost. Then at some point we can drop the library and go standard only.