Fixed Snapshot-related bug

HI @zynthianers!

I think i’ve fixed an old problem. Finally i understanded why trying to reuse engine instances between snapshots is failing. I’ve disabled this “optimization” until i can write a better algorithm for it.
I hope this solves a lot of snapshot-related problems.

The bad part is that snapshots saved after loading several snapshots, specially those using same engines, are probably wrong and should be rebuilt from scratch because routing is broken on them. Broken routing can’t be recovered easily and i would prefer to not add extra (and complex) code for recovering these snapshots. Sorry.

Just update software … and Enjoy!