Story.nextSequenceShuffleIndex() seqCountVal.value! is null

[andrewm-dev]

Inky line {~coat|shoes|beezewaz|silly bandz}! creates error on line 2184 of Story.swift.

Seems to be from seqCountVal.value! equalling nil, which makes the iterationIndex equal -1, thus resulting in a Range error on line 2184.

Looking at the code at a breakpoint on line 2184, I can see that the seqCount is -1 and numElements is 4, which results in -1 and the range error (ie. 0 ... -1 range is invalid).