(Possible) Issues in the tutorial notebook

[karenkathryn]

RE: iraf_specreduce_tutorial.ipynb While looking at this tutorial, I came across a few issues in the following code:

Block 3:

import ccdproc 
from ccdproc import CCDData, ImageFileCollection

and Block 4:

from ccdproc import ImageFileCollection
image_dir = 'exercises/spec/'
ic = ImageFileCollection('exercises/spec/') #read in all FITS files in the directory

Issues:

1. from ccdproc import CCDData, ImageFileCollection and from ccdproc import ImageFileCollection should be covered by import ccdproc
2. In block 4, ImageFileCollection is already imported in block 3
3. ImageFileCollection('exercises/spec/') should be able to be replaced with ImageFileCollection(image_dir) Finally-
4. In the introduction, the link to 'some data' results in a 404 error.