unreferred_proposer/transaction order

[wgr523]

for the same set of blocks, although they arrive in different order for two nodes, the function unreferred_proposer should return the same order.
blockchain unit test different_arrival_same_order should pass, in branch test-interface.

[wgr523]

this may be an enhancement rather than bug?

[yangl1996]

Yeah, it's better categorized as an enhancement.

[bagavi]

@wgr523: "should return the same order." - I dont think this is possible.

[yangl1996]

this should have been fixed by our new voting rule. we need to fix the tests