mbostock/d3 — pull request #2150 by turbolent (2014-12-10 11:48:48+00:00)
Title: Fix clear timeout usage

While working on reimplementing most of the Web APIs required by D3 so it can be used in iOS apps
(see https://github.com/turbolent/d2a), I noticed that `clearTimeout` is used incorrectly. Its definition is `void clearTimeout(long handle);`, which means that it should only be called with a timer ID obtained from `setTimeout` and not with `undefined`.