Revert "make update_anc_database.py work with Python 2"
Revert "make update_anc_database.py work with Python 2"

It doesn't even nearly work in Python 2.7.4 because of files versus buffers,
csv expects bytes not unicode, and headers is not a parameter to urllib.urlopen.
Putting it back to Python 3 so I can at least run the script.

This reverts commit d4bc9dbfba54823cef200d8a3623d50dc0f5f4d1.

dfdx2/ancfinder,dfdx2/ancfinder,codefordc/ancfinder,codefordc/ancfinder,dfdx2/ancfinder,dfdx2/ancfinder,codefordc/ancfinder