Investigate the call of function verify() in contractNipopow.sol

[sdaveas]

Check if everything is legit in .

See a32079a.
This is also related to #9
(That was a false alarm, see #8 (comment))

After aae3a12 the gas results for submitting an invalid contesting_contesting_proof() were the following
see #8 (comment)

Case	gas with previous implementation	gas with current implementation
Block of interest is a common block	6.079.835	2.279.992
Block of interest is only in big chain	6.079.643	2.279.800

[sdaveas]

verify() calls which returns the score of the proof.

Shouldn't this be able to determine the result of verify() directly under certain circumstances?
If the outcome of compare_proofs() is false because the score of existing proof is better than the score of contesting proof, shouldn't the verify() just return false and skip the

    find_ancestors(proof, proof.best_proof[0]);
    return predicate(proof, hash_header(block_of_interest));

part?

[sdaveas]

There is no relation between #8 and #9.
The idea was that in case 1 of #9 a bug was found due to a retrieved result that was different than the expected result. But this is not the case.
The hypothesis of #9 misjudged the following valid scenario: a valid small proof of Ca shouldn't be contested successfully even by a valid proof of chain Cb if Ca is a subset of Cb.