bug 6281: introduce LC::CallNumber::LC for sorting LC call numbers
This replaces the previous hand-coded normalizer. Because
LC::CallNumber::LC appears to reject strings that aren't valid
LC call numbers, significant changes to the test cases were
made as well -- however, the one that really counts is the
last one which verifies the sorting.
To recalculate the call number sort key for each item, it is necessary
to run misc/maintenance/touch_all_items.pl
To test, create item records with the following call numbers, setting
the classification sort to 'lcc':