Fixed fork bug.
I think immutable list needs to be reimplemented using a tree as well.
That would only make the index access slow (o(log n)) - any thoughts
on that ? Does it make sense to have an array based list as well ?
(I've often lists where add/remove operations are not done very often,
but lots of index access happens - however a foreach would be fast in
a tree based list as well)
Removed unit test result files.