Updated readme with a link to the wikipedia article
Updated readme with a link to the wikipedia article

This makes it easier for anyone to find out what interval arithmetic is, and if it might be useful to them.
Jeff-Tian/JavaScriptIntervalArithmetic,Jeff-Tian/JavaScriptIntervalArithmetic,Jeff-Tian/JavaScriptIntervalArithmetic,ollyfg/JavaScriptIntervalArithmetic,Jeff-Tian/JavaScriptIntervalArithmetic