A simple event-driven I/O for Lua, coroutine based.

Support epoll and kevent

• set lua/luajit header path in make.sh
• install scons
• run command: sh make.sh

• put luajit source code directory in ./luajit/
• run command: make

• with luajit command: luajit example/echo_svr.lua
• with lua command: lua example/echo_svr.lua