rewrite using randsample
add console progress info.
delete useless sort on degree
randsample choose sample proportional to value, i.e, here choose nodes proportinal to their degree, so, deg(:, 2) = deg(:, 2) ./ sum(deg(:, 2)) is not necessary.
rewrite using randsample, same as BAmodel_growing except the policy is based on cluster coefficient of node, not the degree.