threaded - true if list should be thread-safe.
root - performance parameter (see above).
maxLevel - performance parameter (see above).
flushLimit - max deleted items to keep cached before
forcing a flush.
useCase - true to be case sensitive in identifiers
freeValue - callback when freeing a value
freeRock - context for freeValue callback
DESCRIPTION
Returns a dictionary. If <threaded> is true, list is
multi-thread safe. <root>, <maxLevel>, and <flushLimit>
act as for skipNewList() (see skiplist.h)