Add a how-to guide for speeding up time with lolex (#1931)
Add a how-to guide for speeding up time with lolex (#1931)

* Add a how-to on speeding up time with lolex
* Explain weird setTimeoutPromise usage in comments

mroderick/Sinon.JS,fatso83/Sinon.JS,mroderick/Sinon.JS,cjohansen/Sinon.JS,fatso83/Sinon.JS,fatso83/Sinon.JS,mroderick/Sinon.JS,cjohansen/Sinon.JS,cjohansen/Sinon.JS