Recursion/Cycles

[krakjoe]

Supporting recursion means we need to be able to collect cyclic references to persistent variables created while copying.

I don't have any good ideas for this yet ...

[krakjoe]

For now, I have added XFAIL to the couple of failing tests ... self referencing structures shouldn't crash like it always has but will cause leaks until we have solved this problem.

I would rather no releases are published until this problem is solved, I will try to give it time over the coming week ... busy week, going back to work.

[realFlowControl]

#325 fixes the leak in the mean time, not nice, but "it works™"