New rendering protocol doesn't work on Windows

[Valtteri Koskivuori]

I don't know much about Windows, and my brief attempt at adding support failed. Ideally for this task we would:

1. Move all socket related code to networking.c
2. Implement a minimal wrapper for the functionality we need that supports posix and win32 APIs (In the same style as thread.c)
3. Rejoice at the newly improved Windows port

Currently networking code is a bit scattered through networking.c and server/worker.c.