Relates to commit 13bf6707

except that this time the problem occured with XML looking like this:

    <subject>and index</subject>
    <subject>ve thinking</subject>
    <subject>innovations</subject>
    <subject>in educ</subject>
    <subject/>

And it was turned into this:

    >>> m=parse_item_metadata('/tmp/alda0000unse_meta.xml')
    >>> m['subject']
    ['and index', 've thinking', 'innovations', 'in educ', None]