Implemented multi-pass merge strategy for PairingHeap
Implementation has been tested for correctness and works correctly. Initial tests indicate that this is slower, contrary to what other people's experiments have shown. The big test for the two-pass are still ongoing on my laptop at the moment. I'll test multi-pass efficiency properly afterwards.
Removed debug code
Removed debugging code from PairingHeap. The rest of the modifications are the result of some additional correctness tests I thought of.
Merge origin/master