lecture 4
Merge branch 'master' of https://github.com/ga-students/DAT_SF_10
updated lab 3, added lab4, added homework 1 key and hw2 files
Merge branch 'master' of https://github.com/ga-students/DAT_SF_10
Merge branch 'master' of https://github.com/ga-students/DAT_SF_10
close out hw1 per standard practice