Fix circular reference of relations which causes a stack overflow.

[HarelM]

• Fixes ToComplete() overflows stack #122

This adds a dictionary of relations in order to pass it down the recursion to use a reference of a relation when trying to create a complete one from it.

I've added a very simple test that throws stack overflow exception before this code change.

[HarelM]

@xivk let me know if you can review, merge this and publish a new version.
I saw it on my production server which causes the service to crash.
Good thing it was restarted automatically, but not a great thing to find out.
I have corrected the relevant relations, but this can obviously happen in the future as OSM data integrity is not guaranteed.
Also would be great if you could publish a non pre release version as we talked about.

THANKS!!