UNIX-II HW: note that curl will not follow redirect on file

[bvoight]

make a note on the homework that the file needs to be downloaded with wget, not curl, since curl does not follow redirects (it will just download the html, which is not helpful).

[bvoight]

We could just change this to the actual link OR download a version and host on github (like the other file, 99_DATA)

[cgreene]

Raw file is now stored here, just in case it disappears. Can also update the link if desired:

https://github.com/greenelab/GCB535/raw/master/99_DATA/Historic_Streets.csv