Groom update

This updates the fix_collection groom to fix_pub_date_elements. Docstring should describe it. It utilizes the new get_singular_node method. The other commits are for deleting the fpage/lpage elements in the meta when they incorrectly exist. This groom goes hand-in-hand with the fix_pub_date_elements one.
I also tried to clean up the file according to pep8 a bit.