Add DetectCycles to detect cycles in compared structs

[posener]

The current comparison fails on stack overflow when given a cyclic struct
(such as a cyclic linked list for example).

This fix adds a new option: DecetctCycles, which finds cycles by adding information
to the path stack, when iterating over pointers.

When a cycle is checked (every time a pointer kind is compared) the path stack
is iterated to find cycles. The comparison of cycles is by they length.

Fixes: #74

[posener]

@dsnet , I can improve this fix.
Instead of saving xAddr, and yAddr in the path stack, I can add a map to the cycleDetector struct that will map the pointer address to the stack length. - then the algorithm becomes O(1) time complexity.

If I make this improve, we can make the cycle detection enabled by default, cause it won't increase the time complexity of the algorithm, and the space complexity will be in the same order it was before.

What do you say?

[posener]

I think that #79 is a better solution, but I'm leaving this one open for your decision.

[dsnet]

I'll comment on #79.