Added Generator Lab and Start on SparseArray

Wasn't able to make much progress on the homework this week, I got the majority of the generator lab working, but am pretty confused about the rest of the assignments. I believe we were going over the sparse array lab in class, the notes of which are in my version, but I am still a bit lost. 

Also added some minor progress in my project, accessing and printing from the API
range() returns a list -- no need to make a a list out of it.

(maybe you've seen python3 code, where range() returns an iterator...)