Update README.md

updates to readme.md

Downloaded PDFs for all course lectures

updated readme.md

Completed course and received certificate on 9-27-2019

Completed week 4 and MP1 programming challenge

Updated readme

Downloaded instructions and files for programming assignment

completed week 4 challenge

completed week 3 challenge and week 4 quiz

Updated readme

changes when switching from PC to mac

Finished wk 3 quiz, challenge. But challenge showing an odd 'InfraError' on Coursera. Too tired now, check tomorrow

completed all week 3 lectures and readings

finished constructors, copy constructors, custom assignment operators