for node >= v0.10.0 use global.setImmediate for nextTick

Tried to stick with your code style.

In node v0.10.0 you get warnings for very recursive calls to process.nextTick. They say to use globale.setImmediate.

This doesn't work but I can't retract a pull request. I thought it was so simple I didn't need to test it. Famous last words.