created a weighted scorer and started writing tests

[kvyh]

I created a weighted scorer that scores by running (in essense):

total_score = np.zeros(len(blocks))
for i, block in enumerate(blocks):
    score = sum([constraint.weight * constraint(....) for constraint in block.constraints])
    score /= sum(weights)
    total_score[i] = score

[bmorris3]

Hey @kvyh, I'm not sure why this PR is still hanging around and not merged – was there anything left to do on this one, or shall I merge it?

[bsipocz]

@bmorris3 - Could we start with the bugfixes, to make sure new features do still work as expected? The green status here is misleading as it was green many month ago before things started to brake.