src: don't lazy-load timer globals

Don't lazy-load setInterval(), setTimeout(), etc.  Most applications are
going to need them and routing every call through NativeModule.require()
and Function#apply() is not exactly efficient.

PR-URL: https://github.com/iojs/io.js/pull/1280


Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>