Init U discretization to N^(1/(2+|U|)) (from initbins = N^(1/3)) bins to help with local minimas when optimizing on many Us
When the conditional info is negative, save the U bins computed on I(x;u) (respectively I(y;u)) for starting I(x;yu) (I(y;xu)) optimization. Also keep the value of I(x;u) and I(y;u) by re-using the same bins.
Fixes #101 with two changes :
N^(1/(2+|U|))(from initbins =N^(1/3)) bins to help with local minimas when optimizing on many UsI(x;u)(respectivelyI(y;u)) for startingI(x;yu)(I(y;xu)) optimization. Also keep the value ofI(x;u)andI(y;u)by re-using the same bins.