Update datacube.py

I didn't comment this as much because it is background files that I didn't deal with directly too much . . . I can go through and do a better job if you think so!

deleted some of the 'pickle' stuff that I don't think is used anymore, but might cause errors?

commented out some of the header stuff that I'm not sure of, some might be useful for WCS stuff though, I'll look into that later