Make Gaussian and Uniform Noise fully compatible with vectors

[markusgft]

@jcarius has proposed the following inspiration

std::default_random_engine generator;
SCALAR mu(0.0);
SCALAR sigma(1.0);
std::normal_distribution<SCALAR> distribution(mu, sigma);
auto normal = [&] (SCALAR)->SCALAR {return distribution(generator);}; // dummy argument required by Eigen

Eigen::Vector3d randVec = Eigen::Vector3d::NullaryExpr(normal);