Removed Jesse Davis's What Is Async, How Does It Work, And When Should I Use It?

The talk is great ([A. Jesse Jiryu Davis: **What Is Async, How Does It Work, And When Should I Use It? - PyCon 2014**](https://www.youtube.com/watch?v=9WV7juNmyE8)) but it doesn't serve the current intention of this markdown file which is focusing pure/built-in Python videos.