Empty vs. undefined, more about Booleans (#13)
Empty vs. undefined, more about Booleans (#13)

* Use Crockford terminology: "Vars which are not explicitly initialized are given the value undefined." https://www.crockford.com/javascript/survey.html

* Change casing of Boolean reserved words. Add section for Boolean NOT operator.

node-girls-australia/js-intro-workshop,node-girls-australia/js-intro-workshop