luarepl-evlib - Use luarepl in a program that's already using an event loop

Some programs already use Lua as a scripting language, and also use an event loop. By linking against the shared library that this project produces and invoking a function, such a program can add a luarepl-powered REPL accessible over a TCP socket.

See also: https://github.com/hoelzro/lua-repl

Limitations

The current implementation is written to work with libev. It shouldn't be too hard to break out the libev-specific logic, but it still remains to be done.

Also, the current implementation will work only with a TCP socket. I don't see a problem with working with UNIX sockets, or even a terminal. Because all of the I/O is done via read() and write(), this should be another "easy" task; it simply remains to be done.