Add `var process = process || {}` to Node.JS's original events.js

Ender.js and other `require` mechanisms can cope with Node.JS's original events.js as long as `process` is defined.

The only reason `process` is used at all in the Node.JS code is for legacy compatibility with C++ modules, so the change is safe. I've been using it in the browser already, I just want to be able to include it in my Ender.JS modules.