added lab7 version 2 with KNN example using PCA
Merge branch 'master' of https://github.com/ga-students/DAT_SF_10
added lab8 on kmeans clusters
Lec 8
adding hw3 key
added solutions for lab8
Merge branch 'master' of https://github.com/ga-students/DAT_SF_10
fixed error in lab 8 solutions
HW4
pulling HW 3