bugfix - fix 'not' operator in NoZebra

bugfix - fix 'not' operator in NoZebra

Corrected bug that prevented the 'not' operator
from working consistently - i.e., a search of
'mice not men' would not always work.

Also added test cases for NoZebra, so far focusing on
NZanalyse and adding and deleting bibs.  A couple of
the test cases are currently known to fail and
therefore are marked TODO.  The tests in question
are to verify that rows in nozebra are removed if
no bib is linked to the relevant word.  However, it
looks like such rows are retained, just with
nozebra.biblionubmers set to ''.  Is there any
reason to keep these rows?

Signed-off-by: Joshua Ferraro <jmf@liblime.com>