changelog-jan-26-2021

Jan 26, 2021
Changelog:
1. Refactor learning outcomes as three paragraphs instead of TOC-like lists to avoid redundancy and cognitive overload. Following CHL's comment.
2. Added relational and logical operators plus a note explaining that this tutorial explains how to search for the many more operators available in R.
3. Moved exercise to test evaluation of complex expressoins using oepartors to just after finishing with basic operators.
4. Added more questions to the quiz on operators