Unresolved merge conflict got committed

This removes it
We check for field indicators, need the same check here

Error tossed by MarcXmlHandler was generic "unable to parse input"

So we'll check for null as w/ field, except that lets not throw out the entire record batch just b/c
of a bad subfield.  Coerce the code to a space when missing/null.
Imperfect, but better than inspecific crashing on a common enough
problem.
Merge pull request #32 from atz/master

Resolve conflict and improve MarcXmlHandler subfield handling